This document describes for libpq was packages for build2. In particular, this understanding will be useful when ugrading to a new upstream version. The original libpq library is packaged together with the PostgreSQL server and client utilities. Most of the libpq source files are located in the src/interfaces/libpq/ directory. Some .c files are symlinked (copied on Windows) from other src/ subdirectories during make. So run configure script in the package root, run make in src/interfaces/libpq/ and then copy source files and symlink targets into libpq/ directory of the build2 package. Note that to obtain the full set of source files that includes Windows-specific ones, you should perform these steps in the MSYS2/MinGW environment. Copy Windows-specific files and strlcpy.c to libpq/win32/ and libpq/non-bsd/ directories respectively. Also copy src/port/pthread-win32.h to libpq/ (next to pthread-win32.c). Note that the library name in the .def file takes precedence over the one specified in the linker command line for both VC and MinGW GCC. So we comment it out in libpq/win32/libpqdll.def. Besides libpq-specific files some of the PostgreSQL common headers are also required. All of them except one (see below) are located in src/include/ subdirectories. Copy them into the libpq/postgresql/ directory, preserving the original directory structure, with the following exceptions: * src/include/pg_config_os.h This is a symlink referencing the target-specific header in the src/include/port/ directory, created by the configure script. Copy these headers under postgresql/port/*/pg_config_os.h path names for the supported target classes. For example, copy src/include/port/linux.h to libpq/postgresql/port/linux/pg_config_os.h. During compilation the '-I.../libpq/postgresql/port/linux' option will be passed to the compiler, so the appropriate pg_config_os.h is picked up. * src/port/pg_config_paths.h This file is generated by src/port/Makfile and defines several directory path macros. Only SYSCONFDIR macro is used in libpq source files. Make the file empty and place it into libpq/postgresql directory. During compilation the macro will be defined with -DSYSCONFDIR preprocessor option. * src/include/pg_config.h.in, src/include/pg_config.h.win32 pg_config_ext.h.in pg_config_ext.h.win32 Use as sources for the manual creation of libpq/postgresql/pg_config.h and libpq/postgresql/pg_config_ext.h, that are used for all target systems. Also add the source headers to the package appending the '.orig' extension to their names. By default the original package installs the library into the /usr/local/pgsql directory. There are also several 'unofficial API' headers installed into the /usr/local/pgsql/include/internal directory. If installing at some custom location that has no postgresql or pgsql words in its path, then it becomes /include/postgresql/internal. We currently do not install unofficial API headers. For the record, the PostgreSQL binary and development packages install libraries and headers into the following directories: Debian/Ubuntu: /usr/lib/x86_64-linux-gnu /usr/include/postgresql /usr/include/postgresql/internal Fedora/RHEL: /usr/lib64 /usr/include /usr/include/pgsql/internal When merge libpq build2 package with a new version of the original package make sure that all the preprocessor include directives reference the packaged header files, rather than PostgreSQL headers that are installed into the system. It's easy to miss some headers in the package if the PostgreSQL development package is installed on the host. To verify the correctness you can build the merged project, concatenate the produced .d files, sort the resulting file removing duplicates and edit the result, leaving only the system headers. Afterwards grep through the remained headers for the 'PostgreSQL' pattern: $ cat `find . -name '*.d'` | sort -u >headers $ emacs headers # Edit, leaving system headers only. $ fgrep PostgreSQL `cat headers` Also make sure that the macros set in libpq/postgresql/pg_config.h are still up to date. For that purpose obtain the macros that are used in the new source base, then obtain the macros (un)defined in the current libpq/postgresql/pg_config.h and compare the sets. That can be achieved running the following commands in the build2 project root directory: $ for m in `cat libpq/postgresql/pg_config.h.in.orig libpq/postgresql/pg_config.h.win32.orig | sed -n 's/.*#\s*\(define\|undef\)\s\{1,\}\([_A-Z0-9]\{1,\}\)\(\s.*\)\{0,1\}$/\2/p' | sort -u`; do if grep -q -e "\b$m\b" `find . -name '*.h' -a ! -name 'pg_config.h' -o -name '*.c'`; then echo "$m" fi done >used-macros $ cat libpq/postgresql/pg_config.h | sed -n 's/#\s*\(define\|undef\)\s\{1,\}\([_A-Z0-9]\{1,\}\)\(\s.*\)\{0,1\}$/\2/p' | sort -u >defined-macros $ diff defined-macros used-macros