Remap Apple Clang 14.0.3 and 15.0.0 to vanilla Clang 14.0 and 15.0

Lately, we started seeing __LIBCPP_VERSION values like 15.0.6 or 16.0.2 which
would suggest the base is 15.0.5 or 16.0.1. But that assumption did not check
out with the actual usage. For example, vanilla Clang 16 should no longer
require -fmodules-ts but the Apple's version (that is presumably based on it)
still does. So the theory here is that Apple upgrades to newer libc++ while
keeping the old compiler. Which means we must be more conservative and assume
something like 15.0.6 is still 14-based.

1 files changed, 14 insertions, 6 deletions

diff --git a/libbuild2/cc/guess.cxx b/libbuild2/cc/guess.cxx
index 8be752f..474185a 100644
--- a/libbuild2/cc/guess.cxx
+++ b/libbuild2/cc/guess.cxx
@@ -2531,6 +2531,15 @@ namespace build2
         // potentially different versions so compile with -v to see which one
         // gets picked up).
         //
+        // Also, lately, we started seeing __LIBCPP_VERSION values like 15.0.6
+        // or 16.0.2 which would suggest the base is 15.0.5 or 16.0.1. But
+        // that assumption did not check out with the actual usage. For
+        // example, vanilla Clang 16 should no longer require -fmodules-ts but
+        // the Apple's version (that is presumably based on it) still does. So
+        // the theory here is that Apple upgrades to newer libc++ while
+        // keeping the old compiler. Which means we must be more conservative
+        // and assume something like 15.0.6 is still 14-based.
+        //
         // Note that this is Apple Clang version and not XCode version.
         //
         // 4.2    -> 3.2svn
@@ -2551,17 +2560,16 @@ namespace build2
         // 12.0.5 -> 10.0 (yes, seriously!)
         // 13.0.0 -> 11.0
         // 13.1.6 -> 12.0
-        // 14.0.0 -> 12.0   (__LIBCPP_VERSION=130000)
-        // 14.0.3 -> 15.0.5 (__LIBCPP_VERSION=150006)
-        // 15.0.0 -> 16.0.1 (__LIBCPP_VERSION=160002)
+        // 14.0.0 -> 12.0 (__LIBCPP_VERSION=130000)
+        // 14.0.3 -> 14.0 (__LIBCPP_VERSION=150006)
+        // 15.0.0 -> 15.0 (__LIBCPP_VERSION=160002)
         //
         uint64_t mj (var_ver->major);
         uint64_t mi (var_ver->minor);
         uint64_t pa (var_ver->patch);
 
-
-        if      (mj >= 15)                          {mj = 16; mi = 0; pa = 1;}
-        else if (mj == 14 && (mi > 0 || pa >= 3))   {mj = 15; mi = 0; pa = 5;}
+        if      (mj >= 15)                          {mj = 15; mi = 0; pa = 0;}
+        else if (mj == 14 && (mi > 0 || pa >= 3))   {mj = 14; mi = 0; pa = 0;}
         else if (mj == 14 || (mj == 13 && mi >= 1)) {mj = 12; mi = 0; pa = 0;}
         else if (mj == 13)                          {mj = 11; mi = 0; pa = 0;}
         else if (mj == 12 && (mi > 0 || pa >= 5))   {mj = 10; mi = 0; pa = 0;}