Get rid of C++ modules related code and rename *.mxx files to *.hxx

46 files changed, 161 insertions, 807 deletions

diff --git a/tests/b-info/driver.cxx b/tests/b-info/driver.cxx
index 963d4e3..6832aaa 100644
--- a/tests/b-info/driver.cxx
+++ b/tests/b-info/driver.cxx
@@ -1,26 +1,12 @@
 // file      : tests/b-info/driver.cxx -*- C++ -*-
 // license   : MIT; see accompanying LICENSE file
 
-#ifndef __cpp_lib_modules_ts
 #include <string>
 #include <iostream>
-#endif
-
-// Other includes.
-
-#ifdef __cpp_modules_ts
-#ifdef __cpp_lib_modules_ts
-import std.core;
-import std.io;
-#endif
-import butl.b;
-import butl.path;
-import butl.utility;    // operator<<(ostream,exception)
-#else
-#include <libbutl/b.mxx>
-#include <libbutl/path.mxx>
-#include <libbutl/utility.mxx>
-#endif
+
+#include <libbutl/b.hxx>
+#include <libbutl/path.hxx>
+#include <libbutl/utility.hxx> // operator<<(ostream,exception)
 
 #undef NDEBUG
 #include <cassert>
diff --git a/tests/backtrace/driver.cxx b/tests/backtrace/driver.cxx
index a8ae99a..ecfa58e 100644
--- a/tests/backtrace/driver.cxx
+++ b/tests/backtrace/driver.cxx
@@ -5,29 +5,14 @@
 #  include <sys/resource.h> // setrlimit()
 #endif
 
-#ifndef __cpp_lib_modules_ts
 #include <string>
 #include <iostream>
 #include <exception>    // set_terminate(), terminate_handler
 #include <system_error>
-#else
-import std.io;
-#endif
-
-// Other includes.
 
-#ifdef __cpp_modules_ts
-#ifdef __cpp_lib_modules_ts
-import std.core;
-#endif
-import butl.process;
-import butl.fdstream;
-import butl.backtrace;
-#else
-#include <libbutl/process.mxx>
-#include <libbutl/fdstream.mxx>
-#include <libbutl/backtrace.mxx>
-#endif
+#include <libbutl/process.hxx>
+#include <libbutl/fdstream.hxx>
+#include <libbutl/backtrace.hxx>
 
 #undef NDEBUG
 #include <cassert>
diff --git a/tests/base64/driver.cxx b/tests/base64/driver.cxx
index d6a95b3..a37a238 100644
--- a/tests/base64/driver.cxx
+++ b/tests/base64/driver.cxx
@@ -1,23 +1,11 @@
 // file      : tests/base64/driver.cxx -*- C++ -*-
 // license   : MIT; see accompanying LICENSE file
 
-#ifndef __cpp_lib_modules_ts
 #include <string>
 #include <vector>
 #include <sstream>
-#endif
-
-// Other includes.
 
-#ifdef __cpp_modules_ts
-#ifdef __cpp_lib_modules_ts
-import std.core;
-import std.io;
-#endif
-import butl.base64;
-#else
-#include <libbutl/base64.mxx>
-#endif
+#include <libbutl/base64.hxx>
 
 #undef NDEBUG
 #include <cassert>
diff --git a/tests/builtin/driver.cxx b/tests/builtin/driver.cxx
index 7a32d8e..7a0193f 100644
--- a/tests/builtin/driver.cxx
+++ b/tests/builtin/driver.cxx
@@ -5,7 +5,6 @@
 #  include <libbutl/win32-utility.hxx>
 #endif
 
-#ifndef __cpp_lib_modules_ts
 #include <string>
 #include <vector>
 #include <chrono>
@@ -16,27 +15,12 @@
 #ifndef _WIN32
 #  include <thread> // this_thread::sleep_for()
 #endif
-#endif
-
-// Other includes.
 
-#ifdef __cpp_modules_ts
-#ifdef __cpp_lib_modules_ts
-import std.core;
-import std.io;
-#endif
-import butl.path;
-import butl.utility;   // eof()
-import butl.builtin;
-import butl.optional;
-import butl.timestamp; // to_stream(duration)
-#else
-#include <libbutl/path.mxx>
-#include <libbutl/utility.mxx>
-#include <libbutl/builtin.mxx>
-#include <libbutl/optional.mxx>
-#include <libbutl/timestamp.mxx>
-#endif
+#include <libbutl/path.hxx>
+#include <libbutl/utility.hxx>   // eof()
+#include <libbutl/builtin.hxx>
+#include <libbutl/optional.hxx>
+#include <libbutl/timestamp.hxx> // to_stream(duration)
 
 #undef NDEBUG
 #include <cassert>
diff --git a/tests/command/driver.cxx b/tests/command/driver.cxx
index e2fe41a..9194c13 100644
--- a/tests/command/driver.cxx
+++ b/tests/command/driver.cxx
@@ -1,36 +1,19 @@
 // file      : tests/command/driver.cxx -*- C++ -*-
 // license   : MIT; see accompanying LICENSE file
 
-#ifndef __cpp_lib_modules_ts
 #include <ios>
 #include <string>
 #include <vector>
 #include <iostream>
 #include <stdexcept>    // invalid_argument
 #include <system_error>
-#endif
 
-// Other includes.
-
-#ifdef __cpp_modules_ts
-#ifdef __cpp_lib_modules_ts
-import std.core;
-import std.io;
-#endif
-import butl.path;
-import butl.path_io;
-import butl.process; // process::print()
-import butl.command;
-import butl.utility;
-import butl.optional;
-#else
-#include <libbutl/path.mxx>
-#include <libbutl/path-io.mxx>
-#include <libbutl/process.mxx>
-#include <libbutl/command.mxx>
-#include <libbutl/utility.mxx>
-#include <libbutl/optional.mxx>
-#endif
+#include <libbutl/path.hxx>
+#include <libbutl/path-io.hxx>
+#include <libbutl/process.hxx>
+#include <libbutl/command.hxx>
+#include <libbutl/utility.hxx>
+#include <libbutl/optional.hxx>
 
 #undef NDEBUG
 #include <cassert>
diff --git a/tests/cpfile/driver.cxx b/tests/cpfile/driver.cxx
index 8891d58..fe01bdd 100644
--- a/tests/cpfile/driver.cxx
+++ b/tests/cpfile/driver.cxx
@@ -1,27 +1,13 @@
 // file      : tests/cpfile/driver.cxx -*- C++ -*-
 // license   : MIT; see accompanying LICENSE file
 
-#ifndef __cpp_lib_modules_ts
 #include <ios>
 #include <string>
 #include <system_error>
-#endif
-
-// Other includes.
 
-#ifdef __cpp_modules_ts
-#ifdef __cpp_lib_modules_ts
-import std.core;
-import std.io;
-#endif
-import butl.path;
-import butl.fdstream;
-import butl.filesystem;
-#else
-#include <libbutl/path.mxx>
-#include <libbutl/fdstream.mxx>
-#include <libbutl/filesystem.mxx>
-#endif
+#include <libbutl/path.hxx>
+#include <libbutl/fdstream.hxx>
+#include <libbutl/filesystem.hxx>
 
 #undef NDEBUG
 #include <cassert>
diff --git a/tests/curl/driver.cxx b/tests/curl/driver.cxx
index 3b0ea43..72faf52 100644
--- a/tests/curl/driver.cxx
+++ b/tests/curl/driver.cxx
@@ -1,33 +1,14 @@
 // file      : tests/curl/driver.cxx -*- C++ -*-
 // license   : MIT; see accompanying LICENSE file
 
-#ifndef __cpp_lib_modules_ts
 #include <iostream>
 #include <system_error>
-#endif
-
-// Other includes.
-
-#ifdef __cpp_modules_ts
-#ifdef __cpp_lib_modules_ts
-import std.core;
-import std.io;
-#endif
-import butl.curl;
-import butl.path;
-import butl.process;
-import butl.utility; // operator<<(ostream, exception)
-import butl.fdstream;
-
-import butl.optional;     // @@ MOD Clang should not be necessary.
-import butl.small_vector; // @@ MOD Clang should not be necessary.
-#else
-#include <libbutl/curl.mxx>
-#include <libbutl/path.mxx>
-#include <libbutl/process.mxx>
-#include <libbutl/utility.mxx>
-#include <libbutl/fdstream.mxx>
-#endif
+
+#include <libbutl/curl.hxx>
+#include <libbutl/path.hxx>
+#include <libbutl/process.hxx>
+#include <libbutl/utility.hxx>  // operator<<(ostream, exception)
+#include <libbutl/fdstream.hxx>
 
 #undef NDEBUG
 #include <cassert>
diff --git a/tests/default-options/driver.cxx b/tests/default-options/driver.cxx
index 94ad189..766dca8 100644
--- a/tests/default-options/driver.cxx
+++ b/tests/default-options/driver.cxx
@@ -1,35 +1,19 @@
 // file      : tests/default-options/driver.cxx -*- C++ -*-
 // license   : MIT; see accompanying LICENSE file
 
-#ifndef __cpp_lib_modules_ts
 #include <limits>
 #include <string>
 #include <vector>
 #include <iostream>
 #include <exception>
 #include <stdexcept> // invalid_argument
-#endif
-
-// Other includes.
-
-#ifdef __cpp_modules_ts
-#ifdef __cpp_lib_modules_ts
-import std.core;
-import std.io;
-#endif
-import butl.path;
-import butl.path_io;
-import butl.optional;
-import butl.fdstream;
-import butl.default_options;
-#else
-#include <libbutl/path.mxx>
-#include <libbutl/path-io.mxx>
-#include <libbutl/utility.mxx>         // eof()
-#include <libbutl/optional.mxx>
-#include <libbutl/fdstream.mxx>
-#include <libbutl/default-options.mxx>
-#endif
+
+#include <libbutl/path.hxx>
+#include <libbutl/path-io.hxx>
+#include <libbutl/utility.hxx>         // eof()
+#include <libbutl/optional.hxx>
+#include <libbutl/fdstream.hxx>
+#include <libbutl/default-options.hxx>
 
 #undef NDEBUG
 #include <cassert>
diff --git a/tests/dir-iterator/driver.cxx b/tests/dir-iterator/driver.cxx
index 0c19037..4a2ff53 100644
--- a/tests/dir-iterator/driver.cxx
+++ b/tests/dir-iterator/driver.cxx
@@ -1,28 +1,13 @@
 // file      : tests/dir-iterator/driver.cxx -*- C++ -*-
 // license   : MIT; see accompanying LICENSE file
 
-#ifndef __cpp_lib_modules_ts
 #include <cstddef> // size_t
 #include <iostream>
-#endif
-
-// Other includes.
-
-#ifdef __cpp_modules_ts
-#ifdef __cpp_lib_modules_ts
-import std.core;
-import std.io;
-#endif
-import butl.path;
-import butl.path_io;
-import butl.utility;
-import butl.filesystem;
-#else
-#include <libbutl/path.mxx>
-#include <libbutl/path-io.mxx>
-#include <libbutl/utility.mxx>    // operator<<(ostream, exception)
-#include <libbutl/filesystem.mxx>
-#endif
+
+#include <libbutl/path.hxx>
+#include <libbutl/path-io.hxx>
+#include <libbutl/utility.hxx>    // operator<<(ostream, exception)
+#include <libbutl/filesystem.hxx>
 
 #undef NDEBUG
 #include <cassert>
diff --git a/tests/entry-time/driver.cxx b/tests/entry-time/driver.cxx
index 0da7fe9..c29837d 100644
--- a/tests/entry-time/driver.cxx
+++ b/tests/entry-time/driver.cxx
@@ -1,29 +1,14 @@
 // file      : tests/entry-time/driver.cxx -*- C++ -*-
 // license   : MIT; see accompanying LICENSE file
 
-#ifndef __cpp_lib_modules_ts
 #include <string>
 #include <chrono>
 #include <iostream>
-#endif
 
-// Other includes.
-
-#ifdef __cpp_modules_ts
-#ifdef __cpp_lib_modules_ts
-import std.core;
-import std.io;
-#endif
-import butl.path;
-import butl.filesystem;
-
-import butl.optional;     // @@ MOD Clang should not be necessary.
-#else
-#include <libbutl/path.mxx>
-#include <libbutl/optional.mxx>
-#include <libbutl/timestamp.mxx>
-#include <libbutl/filesystem.mxx>
-#endif
+#include <libbutl/path.hxx>
+#include <libbutl/optional.hxx>
+#include <libbutl/timestamp.hxx>
+#include <libbutl/filesystem.hxx>
 
 #undef NDEBUG
 #include <cassert>
diff --git a/tests/fdstream/driver.cxx b/tests/fdstream/driver.cxx
index dc657e7..254a03e 100644
--- a/tests/fdstream/driver.cxx
+++ b/tests/fdstream/driver.cxx
@@ -5,7 +5,6 @@
 #  include <libbutl/win32-utility.hxx>
 #endif
 
-#ifndef __cpp_lib_modules_ts
 #ifndef _WIN32
 #  include <chrono>
 #endif
@@ -20,30 +19,12 @@
 #include <utility>   // move()
 #include <iostream>
 #include <exception>
-#endif
-
-// Other includes.
 
-#ifdef __cpp_modules_ts
-#ifdef __cpp_lib_modules_ts
-import std.core;
-import std.io;
-#ifndef _WIN32
-import std.threading;
-#endif
-#endif
-import butl.path;
-import butl.process;
-import butl.fdstream;
-import butl.timestamp;
-import butl.filesystem;
-#else
-#include <libbutl/path.mxx>
-#include <libbutl/process.mxx>
-#include <libbutl/fdstream.mxx>
-#include <libbutl/timestamp.mxx>
-#include <libbutl/filesystem.mxx>
-#endif
+#include <libbutl/path.hxx>
+#include <libbutl/process.hxx>
+#include <libbutl/fdstream.hxx>
+#include <libbutl/timestamp.hxx>
+#include <libbutl/filesystem.hxx>
 
 #undef NDEBUG
 #include <cassert>
diff --git a/tests/link/driver.cxx b/tests/link/driver.cxx
index 6b898f5..db9c195 100644
--- a/tests/link/driver.cxx
+++ b/tests/link/driver.cxx
@@ -1,32 +1,16 @@
 // file      : tests/link/driver.cxx -*- C++ -*-
 // license   : MIT; see accompanying LICENSE file
 
-#ifndef __cpp_lib_modules_ts
 #include <set>
 #include <utility>      // pair
 #include <iostream>     // cerr
 #include <system_error>
-#endif
-
-// Other includes.
 
-#ifdef __cpp_modules_ts
-#ifdef __cpp_lib_modules_ts
-import std.core;
-import std.io;
-#endif
-import butl.path;
-import butl.path_io;
-import butl.utility;
-import butl.fdstream;
-import butl.filesystem;
-#else
-#include <libbutl/path.mxx>
-#include <libbutl/path-io.mxx>
-#include <libbutl/utility.mxx>
-#include <libbutl/fdstream.mxx>
-#include <libbutl/filesystem.mxx>
-#endif
+#include <libbutl/path.hxx>
+#include <libbutl/path-io.hxx>
+#include <libbutl/utility.hxx>
+#include <libbutl/fdstream.hxx>
+#include <libbutl/filesystem.hxx>
 
 #undef NDEBUG
 #include <cassert>
diff --git a/tests/lz4/driver.cxx b/tests/lz4/driver.cxx
index 9004b56..8139c34 100644
--- a/tests/lz4/driver.cxx
+++ b/tests/lz4/driver.cxx
@@ -5,8 +5,8 @@
 #include <exception>
 
 #include <libbutl/lz4.hxx>
-#include <libbutl/fdstream.mxx>
-#include <libbutl/filesystem.mxx> // entry_stat, path_entry()
+#include <libbutl/fdstream.hxx>
+#include <libbutl/filesystem.hxx> // entry_stat, path_entry()
 
 #undef NDEBUG
 #include <cassert>
diff --git a/tests/manifest-parser/driver.cxx b/tests/manifest-parser/driver.cxx
index 859e275..6924321 100644
--- a/tests/manifest-parser/driver.cxx
+++ b/tests/manifest-parser/driver.cxx
@@ -1,27 +1,14 @@
 // file      : tests/manifest-parser/driver.cxx -*- C++ -*-
 // license   : MIT; see accompanying LICENSE file
 
-#ifndef __cpp_lib_modules_ts
 #include <vector>
 #include <string>
 #include <utility> // pair, move()
 #include <sstream>
 #include <iostream>
-#endif
-
-// Other includes.
-
-#ifdef __cpp_modules_ts
-#ifdef __cpp_lib_modules_ts
-import std.core;
-import std.io;
-#endif
-import butl.optional;
-import butl.manifest_parser;
-#else
-#include <libbutl/optional.mxx>
-#include <libbutl/manifest-parser.mxx>
-#endif
+
+#include <libbutl/optional.hxx>
+#include <libbutl/manifest-parser.hxx>
 
 #undef NDEBUG
 #include <cassert>
diff --git a/tests/manifest-rewriter/driver.cxx b/tests/manifest-rewriter/driver.cxx
index d08a6c8..3e8fecb 100644
--- a/tests/manifest-rewriter/driver.cxx
+++ b/tests/manifest-rewriter/driver.cxx
@@ -1,34 +1,18 @@
 // file      : tests/manifest-rewriter/driver.cxx -*- C++ -*-
 // license   : MIT; see accompanying LICENSE file
 
-#ifndef __cpp_lib_modules_ts
 #include <vector>
 #include <string>
 #include <cstdint>   // uint64_t
 #include <utility>   // move()
 #include <iostream>
 #include <exception>
-#endif
-
-// Other includes.
-
-#ifdef __cpp_modules_ts
-#ifdef __cpp_lib_modules_ts
-import std.core;
-import std.io;
-#endif
-import butl.path;
-import butl.optional;
-import butl.fdstream;
-import butl.manifest_parser;
-import butl.manifest_rewriter;
-#else
-#include <libbutl/path.mxx>
-#include <libbutl/optional.mxx>
-#include <libbutl/fdstream.mxx>
-#include <libbutl/manifest-parser.mxx>
-#include <libbutl/manifest-rewriter.mxx>
-#endif
+
+#include <libbutl/path.hxx>
+#include <libbutl/optional.hxx>
+#include <libbutl/fdstream.hxx>
+#include <libbutl/manifest-parser.hxx>
+#include <libbutl/manifest-rewriter.hxx>
 
 #undef NDEBUG
 #include <cassert>
diff --git a/tests/manifest-roundtrip/driver.cxx b/tests/manifest-roundtrip/driver.cxx
index d0bcab9..4cf35e9 100644
--- a/tests/manifest-roundtrip/driver.cxx
+++ b/tests/manifest-roundtrip/driver.cxx
@@ -1,28 +1,13 @@
 // file      : tests/manifest-roundtrip/driver.cxx -*- C++ -*-
 // license   : MIT; see accompanying LICENSE file
 
-#ifndef __cpp_lib_modules_ts
 #include <string>
 #include <iostream>
-#endif
 
-// Other includes.
-
-#ifdef __cpp_modules_ts
-#ifdef __cpp_lib_modules_ts
-import std.core;
-import std.io;
-#endif
-import butl.utility;             // operator<<(ostream, exception)
-import butl.fdstream;
-import butl.manifest_parser;
-import butl.manifest_serializer;
-#else
-#include <libbutl/utility.mxx>
-#include <libbutl/fdstream.mxx>
-#include <libbutl/manifest-parser.mxx>
-#include <libbutl/manifest-serializer.mxx>
-#endif
+#include <libbutl/utility.hxx>             // operator<<(ostream, exception)
+#include <libbutl/fdstream.hxx>
+#include <libbutl/manifest-parser.hxx>
+#include <libbutl/manifest-serializer.hxx>
 
 #undef NDEBUG
 #include <cassert>
diff --git a/tests/manifest-serializer/driver.cxx b/tests/manifest-serializer/driver.cxx
index 59b8ddd..4c09038 100644
--- a/tests/manifest-serializer/driver.cxx
+++ b/tests/manifest-serializer/driver.cxx
@@ -1,25 +1,13 @@
 // file      : tests/manifest-serializer/driver.cxx -*- C++ -*-
 // license   : MIT; see accompanying LICENSE file
 
-#ifndef __cpp_lib_modules_ts
 #include <vector>
 #include <string>
 #include <utility> // pair
 #include <sstream>
 #include <iostream>
-#endif
-
-// Other includes.
-
-#ifdef __cpp_modules_ts
-#ifdef __cpp_lib_modules_ts
-import std.core;
-import std.io;
-#endif
-import butl.manifest_serializer;
-#else
-#include <libbutl/manifest-serializer.mxx>
-#endif
+
+#include <libbutl/manifest-serializer.hxx>
 
 #undef NDEBUG
 #include <cassert>
diff --git a/tests/mventry/driver.cxx b/tests/mventry/driver.cxx
index dc2e2f7..e895ad6 100644
--- a/tests/mventry/driver.cxx
+++ b/tests/mventry/driver.cxx
@@ -1,26 +1,12 @@
 // file      : tests/mventry/driver.cxx -*- C++ -*-
 // license   : MIT; see accompanying LICENSE file
 
-#ifndef __cpp_lib_modules_ts
 #include <iostream>
 #include <system_error>
-#endif
 
-// Other includes.
-
-#ifdef __cpp_modules_ts
-#ifdef __cpp_lib_modules_ts
-import std.core;
-import std.io;
-#endif
-import butl.path;
-import butl.utility;    // operator<<(ostream, exception)
-import butl.filesystem;
-#else
-#include <libbutl/path.mxx>
-#include <libbutl/utility.mxx>
-#include <libbutl/filesystem.mxx>
-#endif
+#include <libbutl/path.hxx>
+#include <libbutl/utility.hxx>    // operator<<(ostream, exception)
+#include <libbutl/filesystem.hxx>
 
 #undef NDEBUG
 #include <cassert>
diff --git a/tests/openssl/driver.cxx b/tests/openssl/driver.cxx
index 450a547..d671c00 100644
--- a/tests/openssl/driver.cxx
+++ b/tests/openssl/driver.cxx
@@ -1,34 +1,15 @@
 // file      : tests/openssl/driver.cxx -*- C++ -*-
 // license   : MIT; see accompanying LICENSE file
 
-#ifndef __cpp_lib_modules_ts
 #include <vector>
 #include <iostream>
 #include <iterator>
 #include <system_error>
-#endif
 
-// Other includes.
-
-#ifdef __cpp_modules_ts
-#ifdef __cpp_lib_modules_ts
-import std.core;
-import std.io;
-#endif
-import butl.path;
-import butl.utility;  // operator<<(ostream, exception)
-import butl.openssl;
-import butl.process;
-import butl.fdstream; // nullfd
-
-import butl.optional;     // @@ MOD Clang should not be necessary.
-import butl.small_vector; // @@ MOD Clang should not be necessary.
-#else
-#include <libbutl/path.mxx>
-#include <libbutl/utility.mxx>
-#include <libbutl/openssl.mxx>
-#include <libbutl/fdstream.mxx>
-#endif
+#include <libbutl/path.hxx>
+#include <libbutl/utility.hxx>  // operator<<(ostream, exception)
+#include <libbutl/openssl.hxx>
+#include <libbutl/fdstream.hxx> // nullfd
 
 #undef NDEBUG
 #include <cassert>
diff --git a/tests/optional/driver.cxx b/tests/optional/driver.cxx
index e73f03e..da09cf5 100644
--- a/tests/optional/driver.cxx
+++ b/tests/optional/driver.cxx
@@ -1,21 +1,10 @@
 // file      : tests/optional/driver.cxx -*- C++ -*-
 // license   : MIT; see accompanying LICENSE file
 
-#ifndef __cpp_lib_modules_ts
 #include <vector>
 #include <utility>    // move()
-#endif
-
-// Other includes.
-
-#ifdef __cpp_modules_ts
-#ifdef __cpp_lib_modules_ts
-import std.core;
-#endif
-import butl.optional;
-#else
-#include <libbutl/optional.mxx>
-#endif
+
+#include <libbutl/optional.hxx>
 
 #undef NDEBUG
 #include <cassert>
diff --git a/tests/pager/driver.cxx b/tests/pager/driver.cxx
index 0d6e1e6..c807ed0 100644
--- a/tests/pager/driver.cxx
+++ b/tests/pager/driver.cxx
@@ -1,26 +1,14 @@
 // file      : tests/pager/driver.cxx -*- C++ -*-
 // license   : MIT; see accompanying LICENSE file
 
-#ifndef __cpp_lib_modules_ts
 #include <ios>      // ios_base::failure
 #include <vector>
 #include <string>
 #include <utility>  // move()
 #include <sstream>
 #include <iostream>
-#endif
-
-// Other includes.
-
-#ifdef __cpp_modules_ts
-#ifdef __cpp_lib_modules_ts
-import std.core;
-import std.io;
-#endif
-import butl.pager;
-#else
-#include <libbutl/pager.mxx>
-#endif
+
+#include <libbutl/pager.hxx>
 
 #undef NDEBUG
 #include <cassert>
diff --git a/tests/path-entry/driver.cxx b/tests/path-entry/driver.cxx
index 13914cd..d9ea2be 100644
--- a/tests/path-entry/driver.cxx
+++ b/tests/path-entry/driver.cxx
@@ -1,34 +1,17 @@
 // file      : tests/path-entry/driver.cxx -*- C++ -*-
 // license   : MIT; see accompanying LICENSE file
 
-#ifndef __cpp_lib_modules_ts
 #include <string>
 #include <iostream>
 #include <stdexcept>    // invalid_argument
 #include <system_error>
-#endif
-
-// Other includes.
-
-#ifdef __cpp_modules_ts
-#ifdef __cpp_lib_modules_ts
-import std.core;
-import std.io;
-#endif
-import butl.path;
-import butl.path-io;
-import butl.utility;    // operator<<(ostream, exception)
-import butl.optional;
-import butl.timestamp;
-import butl.filesystem;
-#else
-#include <libbutl/path.mxx>
-#include <libbutl/path-io.mxx>
-#include <libbutl/utility.mxx>
-#include <libbutl/optional.mxx>
-#include <libbutl/timestamp.mxx>
-#include <libbutl/filesystem.mxx>
-#endif
+
+#include <libbutl/path.hxx>
+#include <libbutl/path-io.hxx>
+#include <libbutl/utility.hxx>    // operator<<(ostream, exception)
+#include <libbutl/optional.hxx>
+#include <libbutl/timestamp.hxx>
+#include <libbutl/filesystem.hxx>
 
 #undef NDEBUG
 #include <cassert>
diff --git a/tests/path/driver.cxx b/tests/path/driver.cxx
index 9f85d6b..3124c13 100644
--- a/tests/path/driver.cxx
+++ b/tests/path/driver.cxx
@@ -1,25 +1,12 @@
 // file      : tests/path/driver.cxx -*- C++ -*-
 // license   : MIT; see accompanying LICENSE file
 
-#ifndef __cpp_lib_modules_ts
 #include <sstream>
 #include <iostream>
 #include <type_traits>
-#endif
-
-// Other includes.
 
-#ifdef __cpp_modules_ts
-#ifdef __cpp_lib_modules_ts
-import std.core;
-import std.io;
-#endif
-import butl.path;
-//import butl.path_io;
-#else
-#include <libbutl/path.mxx>
-//#include <libbutl/path-io.mxx>
-#endif
+#include <libbutl/path.hxx>
+//#include <libbutl/path-io.hxx>
 
 #undef NDEBUG
 #include <cassert>
diff --git a/tests/prefix-map/driver.cxx b/tests/prefix-map/driver.cxx
index 0628abf..8ed35ea 100644
--- a/tests/prefix-map/driver.cxx
+++ b/tests/prefix-map/driver.cxx
@@ -1,22 +1,10 @@
 // file      : tests/prefix-map/driver.cxx -*- C++ -*-
 // license   : MIT; see accompanying LICENSE file
 
-#ifndef __cpp_lib_modules_ts
 #include <string>
 #include <iostream>
-#endif
-
-// Other includes.
-
-#ifdef __cpp_modules_ts
-#ifdef __cpp_lib_modules_ts
-import std.core;
-import std.io;
-#endif
-import butl.prefix_map;
-#else
-#include <libbutl/prefix-map.mxx>
-#endif
+
+#include <libbutl/prefix-map.hxx>
 
 #undef NDEBUG
 #include <cassert>
diff --git a/tests/process-run/driver.cxx b/tests/process-run/driver.cxx
index c851666..032f890 100644
--- a/tests/process-run/driver.cxx
+++ b/tests/process-run/driver.cxx
@@ -1,29 +1,13 @@
 // file      : tests/process-run/driver.cxx -*- C++ -*-
 // license   : MIT; see accompanying LICENSE file
 
-#ifndef __cpp_lib_modules_ts
 #include <string>
 #include <iostream>
-#endif
-
-// Other includes.
-
-#ifdef __cpp_modules_ts
-#ifdef __cpp_lib_modules_ts
-import std.core;
-import std.io;
-#endif
-import butl.path;
-import butl.process;
-import butl.optional; // @@ MOD Clang shouldn't be needed.
-import butl.fdstream;
-import butl.small_vector;
-#else
-#include <libbutl/path.mxx>
-#include <libbutl/process.mxx>
-#include <libbutl/fdstream.mxx>
-#include <libbutl/small-vector.mxx>
-#endif
+
+#include <libbutl/path.hxx>
+#include <libbutl/process.hxx>
+#include <libbutl/fdstream.hxx>
+#include <libbutl/small-vector.hxx>
 
 #undef NDEBUG
 #include <cassert>
diff --git a/tests/process-term/driver.cxx b/tests/process-term/driver.cxx
index 90afc96..799757c 100644
--- a/tests/process-term/driver.cxx
+++ b/tests/process-term/driver.cxx
@@ -10,7 +10,6 @@
 #  include <libbutl/win32-utility.hxx>
 #endif
 
-#ifndef __cpp_lib_modules_ts
 #include <string>
 #include <cerrno>   // ERANGE
 #include <utility>  // move()
@@ -21,23 +20,10 @@
 #ifndef _WIN32
 #  include <chrono>
 #endif
-#endif
-
-// Other includes.
 
-#ifdef __cpp_modules_ts
-#ifdef __cpp_lib_modules_ts
-import std.core;
-import std.io;
-#endif
-import butl.process;
-import butl.optional;
-import butl.fdstream;
-#else
-#include <libbutl/process.mxx>
-#include <libbutl/optional.mxx>
-#include <libbutl/fdstream.mxx>
-#endif
+#include <libbutl/process.hxx>
+#include <libbutl/optional.hxx>
+#include <libbutl/fdstream.hxx>
 
 #undef NDEBUG
 #include <cassert>
diff --git a/tests/process/driver.cxx b/tests/process/driver.cxx
index ab5006a..1ee5710 100644
--- a/tests/process/driver.cxx
+++ b/tests/process/driver.cxx
@@ -1,7 +1,6 @@
 // file      : tests/process/driver.cxx -*- C++ -*-
 // license   : MIT; see accompanying LICENSE file
 
-#ifndef __cpp_lib_modules_ts
 #include <ios>
 #include <string>
 #include <vector>
@@ -10,30 +9,14 @@
 #include <iterator>  // istreambuf_iterator, ostream_iterator
 #include <algorithm> // copy()
 #include <iostream>
-#endif
-
-// Other includes.
 
-#ifdef __cpp_modules_ts
-#ifdef __cpp_lib_modules_ts
-import std.core;
-import std.io;
-#endif
-import butl.path;
-import butl.utility;  // setenv(), getenv()
-import butl.process;
-import butl.optional;
-import butl.fdstream;
-import butl.timestamp;
-#else
-#include <libbutl/path.mxx>
-#include <libbutl/utility.mxx>
-#include <libbutl/process.mxx>
-#include <libbutl/process-io.mxx>
-#include <libbutl/optional.mxx>
-#include <libbutl/fdstream.mxx>
-#include <libbutl/timestamp.mxx>
-#endif
+#include <libbutl/path.hxx>
+#include <libbutl/utility.hxx>    // setenv(), getenv()
+#include <libbutl/process.hxx>
+#include <libbutl/process-io.hxx>
+#include <libbutl/optional.hxx>
+#include <libbutl/fdstream.hxx>
+#include <libbutl/timestamp.hxx>
 
 #undef NDEBUG
 #include <cassert>
diff --git a/tests/progress/driver.cxx b/tests/progress/driver.cxx
index 68952a7..f1a257c 100644
--- a/tests/progress/driver.cxx
+++ b/tests/progress/driver.cxx
@@ -8,36 +8,16 @@
 #  include <io.h> //_write()
 #endif
 
-#ifndef __cpp_lib_modules_ts
 #include <string>
 #include <cstddef>  // size_t
 #include <iostream>
 #ifndef _WIN32
 #  include <thread> // this_thread::sleep_for()
 #endif
-#endif
-
-// Other includes.
-
-#ifdef __cpp_modules_ts
-#ifdef __cpp_lib_modules_ts
-import std.core;
-import std.io;
-#ifndef _WIN32
-import std.threading;
-#endif
-#endif
-import butl.process;
-import butl.fdstream;
-import butl.diagnostics;
 
-import butl.optional;     // @@ MOD Clang should not be necessary.
-import butl.small_vector; // @@ MOD Clang should not be necessary.
-#else
-#include <libbutl/process.mxx>
-#include <libbutl/fdstream.mxx>    // fdopen_null(), stderr_fd()
-#include <libbutl/diagnostics.mxx>
-#endif
+#include <libbutl/process.hxx>
+#include <libbutl/fdstream.hxx>    // fdopen_null(), stderr_fd()
+#include <libbutl/diagnostics.hxx>
 
 #undef NDEBUG
 #include <cassert>
diff --git a/tests/project-name/driver.cxx b/tests/project-name/driver.cxx
index 8c5b206..ac1c898 100644
--- a/tests/project-name/driver.cxx
+++ b/tests/project-name/driver.cxx
@@ -1,26 +1,14 @@
 // file      : tests/project-name/driver.cxx -*- C++ -*-
 // license   : MIT; see accompanying LICENSE file
 
-#ifndef __cpp_lib_modules_ts
 #include <ios>       // ios::*bit
 #include <string>
 #include <iostream>
 #include <stdexcept> // invalid_argument
-#endif
-
-// Other includes.
-
-#ifdef __cpp_modules_ts
-#ifdef __cpp_lib_modules_ts
-import std.core;
-import std.io;
-#endif
-import butl.utility;      // operator<<(ostream,exception), eof(), *case()
-import butl.project_name;
-#else
-#include <libbutl/utility.mxx>
-#include <libbutl/project-name.mxx>
-#endif
+
+#include <libbutl/utility.hxx>      // operator<<(ostream,exception), eof(),
+                                    // *case()
+#include <libbutl/project-name.hxx>
 
 #undef NDEBUG
 #include <cassert>
diff --git a/tests/regex/driver.cxx b/tests/regex/driver.cxx
index ce707b8..f8363e1 100644
--- a/tests/regex/driver.cxx
+++ b/tests/regex/driver.cxx
@@ -1,29 +1,15 @@
 // file      : tests/regex/driver.cxx -*- C++ -*-
 // license   : MIT; see accompanying LICENSE file
 
-#ifndef __cpp_lib_modules_ts
 #include <regex>
 #include <string>
 #include <utility>   // pair
 #include <iostream>
 #include <stdexcept> // invalid_argument
 #include <exception>
-#endif
 
-// Other includes.
-
-#ifdef __cpp_modules_ts
-#ifdef __cpp_lib_modules_ts
-import std.core;
-import std.io;
-import std.regex; // @@ MOD TODO: shouldn't be necessary (re-export).
-#endif
-import butl.regex;
-import butl.utility; // operator<<(ostream, exception)
-#else
-#include <libbutl/regex.mxx>
-#include <libbutl/utility.mxx>
-#endif
+#include <libbutl/regex.hxx>
+#include <libbutl/utility.hxx> // operator<<(ostream, exception)
 
 #undef NDEBUG
 #include <cassert>
diff --git a/tests/semantic-version/driver.cxx b/tests/semantic-version/driver.cxx
index ac6bf33..2bdd415 100644
--- a/tests/semantic-version/driver.cxx
+++ b/tests/semantic-version/driver.cxx
@@ -1,21 +1,9 @@
 // file      : tests/semantic-version/driver.cxx -*- C++ -*-
 // license   : MIT; see accompanying LICENSE file
 
-#ifndef __cpp_lib_modules_ts
 #include <iostream>
-#endif
 
-// Other includes.
-
-#ifdef __cpp_modules_ts
-#ifdef __cpp_lib_modules_ts
-import std.core;
-import std.io;
-#endif
-import butl.semantic_version;
-#else
-#include <libbutl/semantic-version.mxx>
-#endif
+#include <libbutl/semantic-version.hxx>
 
 #undef NDEBUG
 #include <cassert>
diff --git a/tests/sendmail/driver.cxx b/tests/sendmail/driver.cxx
index a29650c..3b97202 100644
--- a/tests/sendmail/driver.cxx
+++ b/tests/sendmail/driver.cxx
@@ -1,32 +1,13 @@
 // file      : tests/sendmail/driver.cxx -*- C++ -*-
 // license   : MIT; see accompanying LICENSE file
 
-#ifndef __cpp_lib_modules_ts
 #include <iostream>
 #include <system_error>
-#endif
 
-// Other includes.
-
-#ifdef __cpp_modules_ts
-#ifdef __cpp_lib_modules_ts
-import std.core;
-import std.io;
-#endif
-import butl.path;
-import butl.process;
-import butl.utility;  // operator<<(ostream, exception)
-import butl.sendmail;
-import butl.fdstream;
-
-import butl.optional;     // @@ MOD Clang should not be necessary.
-import butl.small_vector; // @@ MOD Clang should not be necessary.
-#else
-#include <libbutl/path.mxx>
-#include <libbutl/process.mxx>
-#include <libbutl/utility.mxx>
-#include <libbutl/sendmail.mxx>
-#endif
+#include <libbutl/path.hxx>
+#include <libbutl/process.hxx>
+#include <libbutl/utility.hxx>  // operator<<(ostream, exception)
+#include <libbutl/sendmail.hxx>
 
 #undef NDEBUG
 #include <cassert>
diff --git a/tests/sha1/driver.cxx b/tests/sha1/driver.cxx
index cb648db..1e8e254 100644
--- a/tests/sha1/driver.cxx
+++ b/tests/sha1/driver.cxx
@@ -1,27 +1,13 @@
 // file      : tests/sha1/driver.cxx -*- C++ -*-
 // license   : MIT; see accompanying LICENSE file
 
-#ifndef __cpp_lib_modules_ts
 #include <string>
 #include <cstddef> // size_t
-#endif
-
-// Other includes.
-
-#ifdef __cpp_modules_ts
-#ifdef __cpp_lib_modules_ts
-import std.core;
-#endif
-import butl.sha1;
-import butl.path;
-import butl.fdstream;
-import butl.filesystem;
-#else
-#include <libbutl/sha1.mxx>
-#include <libbutl/path.mxx>
-#include <libbutl/fdstream.mxx>
-#include <libbutl/filesystem.mxx> // auto_rmfile
-#endif
+
+#include <libbutl/sha1.hxx>
+#include <libbutl/path.hxx>
+#include <libbutl/fdstream.hxx>
+#include <libbutl/filesystem.hxx> // auto_rmfile
 
 #undef NDEBUG
 #include <cassert>
diff --git a/tests/sha256/driver.cxx b/tests/sha256/driver.cxx
index 3d2f69e..30dfa49 100644
--- a/tests/sha256/driver.cxx
+++ b/tests/sha256/driver.cxx
@@ -1,27 +1,13 @@
 // file      : tests/sha256/driver.cxx -*- C++ -*-
 // license   : MIT; see accompanying LICENSE file
 
-#ifndef __cpp_lib_modules_ts
 #include <string>
 #include <cstddef> // size_t
-#endif
-
-// Other includes.
-
-#ifdef __cpp_modules_ts
-#ifdef __cpp_lib_modules_ts
-import std.core;
-#endif
-import butl.path;
-import butl.sha256;
-import butl.fdstream;
-import butl.filesystem;
-#else
-#include <libbutl/path.mxx>
-#include <libbutl/sha256.mxx>
-#include <libbutl/fdstream.mxx>
-#include <libbutl/filesystem.mxx> // auto_rmfile
-#endif
+
+#include <libbutl/path.hxx>
+#include <libbutl/sha256.hxx>
+#include <libbutl/fdstream.hxx>
+#include <libbutl/filesystem.hxx> // auto_rmfile
 
 #undef NDEBUG
 #include <cassert>
diff --git a/tests/small-forward-list/driver.cxx b/tests/small-forward-list/driver.cxx
index 1b8a14f..1cfea77 100644
--- a/tests/small-forward-list/driver.cxx
+++ b/tests/small-forward-list/driver.cxx
@@ -1,22 +1,10 @@
 // file      : tests/small-forward-list/driver.cxx -*- C++ -*-
 // license   : MIT; see accompanying LICENSE file
 
-#ifndef __cpp_lib_modules_ts
 #include <string>
 #include <iostream>
-#endif
-
-// Other includes.
-
-#ifdef __cpp_modules_ts
-#ifdef __cpp_lib_modules_ts
-import std.core;
-import std.io;
-#endif
-import butl.small_forward_list;
-#else
-#include <libbutl/small-forward-list.mxx>
-#endif
+
+#include <libbutl/small-forward-list.hxx>
 
 #undef NDEBUG
 #include <cassert>
diff --git a/tests/small-list/driver.cxx b/tests/small-list/driver.cxx
index cced91d..8e2fb6e 100644
--- a/tests/small-list/driver.cxx
+++ b/tests/small-list/driver.cxx
@@ -1,22 +1,10 @@
 // file      : tests/small-list/driver.cxx -*- C++ -*-
 // license   : MIT; see accompanying LICENSE file
 
-#ifndef __cpp_lib_modules_ts
 #include <string>
 #include <iostream>
-#endif
-
-// Other includes.
 
-#ifdef __cpp_modules_ts
-#ifdef __cpp_lib_modules_ts
-import std.core;
-import std.io;
-#endif
-import butl.small_list;
-#else
-#include <libbutl/small-list.mxx>
-#endif
+#include <libbutl/small-list.hxx>
 
 #undef NDEBUG
 #include <cassert>
diff --git a/tests/small-vector/driver.cxx b/tests/small-vector/driver.cxx
index be8e6d8..cc012fc 100644
--- a/tests/small-vector/driver.cxx
+++ b/tests/small-vector/driver.cxx
@@ -1,22 +1,10 @@
 // file      : tests/small-vector/driver.cxx -*- C++ -*-
 // license   : MIT; see accompanying LICENSE file
 
-#ifndef __cpp_lib_modules_ts
 #include <string>
 #include <iostream>
-#endif
-
-// Other includes.
-
-#ifdef __cpp_modules_ts
-#ifdef __cpp_lib_modules_ts
-import std.core;
-import std.io;
-#endif
-import butl.small_vector;
-#else
-#include <libbutl/small-vector.mxx>
-#endif
+
+#include <libbutl/small-vector.hxx>
 
 #undef NDEBUG
 #include <cassert>
diff --git a/tests/standard-version/driver.cxx b/tests/standard-version/driver.cxx
index dbd24fc..29cad54 100644
--- a/tests/standard-version/driver.cxx
+++ b/tests/standard-version/driver.cxx
@@ -1,29 +1,15 @@
 // file      : tests/standard-version/driver.cxx -*- C++ -*-
 // license   : MIT; see accompanying LICENSE file
 
-#ifndef __cpp_lib_modules_ts
 #include <ios>       // ios::failbit, ios::badbit
 #include <string>
 #include <cstdint>   // uint*_t
 #include <iostream>
 #include <stdexcept> // invalid_argument
-#endif
-
-// Other includes.
-
-#ifdef __cpp_modules_ts
-#ifdef __cpp_lib_modules_ts
-import std.core;
-import std.io;
-#endif
-import butl.utility;          // operator<<(ostream,exception), eof()
-import butl.optional;
-import butl.standard_version;
-#else
-#include <libbutl/utility.mxx>
-#include <libbutl/optional.mxx>
-#include <libbutl/standard-version.mxx>
-#endif
+
+#include <libbutl/utility.hxx>          // operator<<(ostream,exception), eof()
+#include <libbutl/optional.hxx>
+#include <libbutl/standard-version.hxx>
 
 #undef NDEBUG
 #include <cassert>
diff --git a/tests/strcase/driver.cxx b/tests/strcase/driver.cxx
index 48e77f2..8e964a6 100644
--- a/tests/strcase/driver.cxx
+++ b/tests/strcase/driver.cxx
@@ -1,20 +1,9 @@
 // file      : tests/strcase/driver.cxx -*- C++ -*-
 // license   : MIT; see accompanying LICENSE file
 
-#ifndef __cpp_lib_modules_ts
 #include <string>
-#endif
 
-// Other includes.
-
-#ifdef __cpp_modules_ts
-#ifdef __cpp_lib_modules_ts
-import std.core;
-#endif
-import butl.utility;
-#else
-#include <libbutl/utility.mxx>
-#endif
+#include <libbutl/utility.hxx>
 
 #undef NDEBUG
 #include <cassert>
diff --git a/tests/string-parser/driver.cxx b/tests/string-parser/driver.cxx
index 2e47e4a..8cba912 100644
--- a/tests/string-parser/driver.cxx
+++ b/tests/string-parser/driver.cxx
@@ -1,25 +1,12 @@
 // file      : tests/string-parser/driver.cxx -*- C++ -*-
 // license   : MIT; see accompanying LICENSE file
 
-#ifndef __cpp_lib_modules_ts
 #include <string>
 #include <vector>
 #include <iostream>
-#endif
-
-// Other includes.
-
-#ifdef __cpp_modules_ts
-#ifdef __cpp_lib_modules_ts
-import std.core;
-import std.io;
-#endif
-import butl.utility;       // operator<<(ostream,exception)
-import butl.string_parser;
-#else
-#include <libbutl/utility.mxx>
-#include <libbutl/string-parser.mxx>
-#endif
+
+#include <libbutl/utility.hxx>       // operator<<(ostream,exception)
+#include <libbutl/string-parser.hxx>
 
 #undef NDEBUG
 #include <cassert>
diff --git a/tests/tab-parser/driver.cxx b/tests/tab-parser/driver.cxx
index e9cd36f..99c19d9 100644
--- a/tests/tab-parser/driver.cxx
+++ b/tests/tab-parser/driver.cxx
@@ -1,24 +1,11 @@
 // file      : tests/tab-parser/driver.cxx -*- C++ -*-
 // license   : MIT; see accompanying LICENSE file
 
-#ifndef __cpp_lib_modules_ts
 #include <string>
 #include <iostream>
-#endif
 
-// Other includes.
-
-#ifdef __cpp_modules_ts
-#ifdef __cpp_lib_modules_ts
-import std.core;
-import std.io;
-#endif
-import butl.utility;    // operator<<(ostream,exception)
-import butl.tab_parser;
-#else
-#include <libbutl/utility.mxx>
-#include <libbutl/tab-parser.mxx>
-#endif
+#include <libbutl/utility.hxx>    // operator<<(ostream,exception)
+#include <libbutl/tab-parser.hxx>
 
 #undef NDEBUG
 #include <cassert>
diff --git a/tests/target-triplet/driver.cxx b/tests/target-triplet/driver.cxx
index 9cd7c2b..6dcb77e 100644
--- a/tests/target-triplet/driver.cxx
+++ b/tests/target-triplet/driver.cxx
@@ -1,23 +1,11 @@
 // file      : tests/target-triplet/driver.cxx -*- C++ -*-
 // license   : MIT; see accompanying LICENSE file
 
-#ifndef __cpp_lib_modules_ts
 #include <string>
 #include <iostream>
 #include <stdexcept> // invalid_argument
-#endif
-
-// Other includes.
-
-#ifdef __cpp_modules_ts
-#ifdef __cpp_lib_modules_ts
-import std.core;
-import std.io;
-#endif
-import butl.target_triplet;
-#else
-#include <libbutl/target-triplet.mxx>
-#endif
+
+#include <libbutl/target-triplet.hxx>
 
 #undef NDEBUG
 #include <cassert>
diff --git a/tests/timestamp/driver.cxx b/tests/timestamp/driver.cxx
index 0ea2b38..11f328a 100644
--- a/tests/timestamp/driver.cxx
+++ b/tests/timestamp/driver.cxx
@@ -3,26 +3,14 @@
 
 #include <time.h> // tzset() (POSIX), _tzset() (Windows)
 
-#ifndef __cpp_lib_modules_ts
 #include <chrono>
 #include <locale>
 #include <clocale>
 #include <sstream>
 #include <iomanip>
 #include <system_error>
-#endif
-
-// Other includes.
 
-#ifdef __cpp_modules_ts
-#ifdef __cpp_lib_modules_ts
-import std.core;
-import std.io;
-#endif
-import butl.timestamp;
-#else
-#include <libbutl/timestamp.mxx>
-#endif
+#include <libbutl/timestamp.hxx>
 
 #undef NDEBUG
 #include <cassert>
diff --git a/tests/url/driver.cxx b/tests/url/driver.cxx
index 02bb5b8..869eed5 100644
--- a/tests/url/driver.cxx
+++ b/tests/url/driver.cxx
@@ -1,27 +1,14 @@
 // file      : tests/url/driver.cxx -*- C++ -*-
 // license   : MIT; see accompanying LICENSE file
 
-#ifndef __cpp_lib_modules_ts
 #include <string>
 #include <utility>   // move()
 #include <iostream>
 #include <iterator>  // back_inserter
 #include <stdexcept> // invalid_argument
-#endif
-
-// Other includes.
-
-#ifdef __cpp_modules_ts
-#ifdef __cpp_lib_modules_ts
-import std.core;
-import std.io;
-#endif
-import butl.url;
-import butl.utility; // operator<<(ostream, exception)
-#else
-#include <libbutl/url.mxx>
-#include <libbutl/utility.mxx>
-#endif
+
+#include <libbutl/url.hxx>
+#include <libbutl/utility.hxx> // operator<<(ostream, exception)
 
 #undef NDEBUG
 #include <cassert>
diff --git a/tests/utf8/driver.cxx b/tests/utf8/driver.cxx
index db98aa6..ccc2870 100644
--- a/tests/utf8/driver.cxx
+++ b/tests/utf8/driver.cxx
@@ -1,22 +1,10 @@
 // file      : tests/utf8/driver.cxx -*- C++ -*-
 // license   : MIT; see accompanying LICENSE file
 
-#ifndef __cpp_lib_modules_ts
 #include <string>
-#endif
-
-// Other includes.
-
-#ifdef __cpp_modules_ts
-#ifdef __cpp_lib_modules_ts
-import std.core;
-#endif
-import butl.utf8;
-import butl.utility;
-#else
-#include <libbutl/utf8.mxx>
-#include <libbutl/utility.mxx>
-#endif
+
+#include <libbutl/utf8.hxx>
+#include <libbutl/utility.hxx>
 
 #undef NDEBUG
 #include <cassert>
diff --git a/tests/wildcard/driver.cxx b/tests/wildcard/driver.cxx
index bd6a00d..9419a79 100644
--- a/tests/wildcard/driver.cxx
+++ b/tests/wildcard/driver.cxx
@@ -1,34 +1,18 @@
 // file      : tests/wildcard/driver.cxx -*- C++ -*-
 // license   : MIT; see accompanying LICENSE file
 
-#ifndef __cpp_lib_modules_ts
 #include <map>
 #include <string>
 #include <vector>
 #include <algorithm> // sort()
 #include <exception>
 #include <iostream>
-#endif
-
-// Other includes.
 
-#ifdef __cpp_modules_ts
-#ifdef __cpp_lib_modules_ts
-import std.core;
-import std.io;
-#endif
-import butl.path;
-import butl.utility;    // operator<<(ostream, exception)
-import butl.optional;
-import butl.filesystem;
-import butl.path_pattern;
-#else
-#include <libbutl/path.mxx>
-#include <libbutl/utility.mxx>
-#include <libbutl/optional.mxx>
-#include <libbutl/filesystem.mxx>
-#include <libbutl/path-pattern.mxx>
-#endif
+#include <libbutl/path.hxx>
+#include <libbutl/utility.hxx>      // operator<<(ostream, exception)
+#include <libbutl/optional.hxx>
+#include <libbutl/filesystem.hxx>
+#include <libbutl/path-pattern.hxx>
 
 #undef NDEBUG
 #include <cassert>