On Thu, Jan 14, 2021 at 5:13 AM Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
> I have a different complaint, using Big Sur and Xcode 12.3:
>
> /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/ranlib: file: libpgport.a(pread.o) has no symbols
> /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/ranlib: file: libpgport_shlib.a(pread_shlib.o) has no symbols
> /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/ranlib: file: libpgport_srv.a(pread_srv.o) has no symbols
>
> Looks like we need to be more careful about not including pread.c
> in the build unless it actually has code to contribute.
I did it that way because it made it easy to test different
combinations of the replacements on computers that do actually have
pwrite and pwritev, just by tweaking pg_config.h. Here's an attempt
to do it with AC_REPLACE_FUNCS, which avoids creating empty .o files.
It means that to test the replacements on modern systems you have to
tweak pg_config.h and also add the relevant .o files to LIBOBJS in
src/Makefile.global, but that seems OK.