PostgreSQL Build Instructions
As of writing, we're using PostgreSQL v9.6.9
https://www.postgresql.org/ftp/source/
After building, libpq can be found in src/interfaces/libpq/
Windows
https://www.postgresql.org/docs/9.6/install-windows-libpq.html
Change src/interfaces/win32.mak line 35 from OPT=/O2 /MD to OPT=/O2 /MT. Library will be in interfaces\libpq\Release\libpq.lib.
You have to delete the interfaces\libpq\Release folder between x86 and x86_64 builds.
Mac
For x86 or x86_64 add -m32 or -m64 to CFLAGS
CFLAGS='-mmacosx-version-min=10.7' ./configure && make
Linux
For x86 or x86_64 add -m32 or -m64 to CFLAGS
CFLAGS='-fPIC' ./configure --without-readline && make