New comment by pullmoll on void-packages repository

https://github.com/void-linux/void-packages/pull/24258#issuecomment-674384131

Comment:
Trying to bootstrap with this PR merged fails when building `gdbm`:
```
…
  CCLD     gdbmtool
/usr/bin/ld: ./libgdbmapp.a(parseopt.o):(.bss+0x8): multiple definition of `parseopt_program_args'; gdbmtool.o:(.data.rel.local+0x260): first defined here
/usr/bin/ld: ./libgdbmapp.a(parseopt.o):(.bss+0x10): multiple definition of `parseopt_program_doc'; gdbmtool.o:(.data.rel.local+0x268): first defined here
collect2: error: ld returned 1 exit status
make[3]: *** [Makefile:656: gdbmtool] Error 1
make[3]: Leaving directory '/builddir/gdbm-1.18.1/src'
make[2]: *** [Makefile:499: all] Error 2
make[2]: Leaving directory '/builddir/gdbm-1.18.1/src'
make[1]: *** [Makefile:464: all-recursive] Error 1
make[1]: Leaving directory '/builddir/gdbm-1.18.1'
make: *** [Makefile:396: all] Error 2
=> ERROR: gdbm-1.18.1_1: do_build: '${make_cmd} ${makejobs} ${make_build_args} ${make_build_target}' exited with 2
=> ERROR:   in do_build() at common/build-style/gnu-configure.sh:13
```

Edit: Adding `CFLAGS="-fcommon"` fixes it.