FTBFS + PKGBUILD improvement

Description:

Was unable to compile a debug build today :

main.c: In function ‘main_cleanup’:
main.c:353:5: error: implicit declaration of function ‘SIG_deregister’; did you mean ‘SIG_register’? [-Wimplicit-function-declaration]
  353 |     SIG_deregister(SIGABRT, main_cleanup);
      |     ^~~~~~~~~~~~~~
      |     SIG_register
make[2]: *** [Makefile:660: main.o] Error 1
...

Additional info:

redhat used this patch to address this (or a similar issue): https://src.fedoraproject.org/rpms/cvs/pull-request/3#request_diff

• package version(s): 1.11.23-15

Steps to reproduce:

1. pactl repo clone cvs
2. makepkg