regex.o refuse to build with --enable-gcc-warnings

[Charlie Brown]

regex.o refuse to build when I build from tar git source (with
latest gnulib source) today, which turns on --enable-gcc-warnings by
default.

I can finish the compilation by .configure --disable-gcc-warnings.

Can you fix this warning here?

Thanks a lot!
And thank you for making such good tools!

-------------------------------------------------------------------------------------------------------------------------------------------------
In file included from regex.c:70:0:
regcomp.c: In function 'rpl_regfree':
regex_internal.h:77:26: error: statement with no effect [-Werror=unused-value]
 # define lock_fini(lock) 0
                          ^
regcomp.c:669:7: note: in expansion of macro 'lock_fini'
       lock_fini (dfa->lock);
       ^
regcomp.c: In function 're_compile_internal':
regex_internal.h:77:26: error: statement with no effect [-Werror=unused-value]
 # define lock_fini(lock) 0
                          ^
regcomp.c:814:7: note: in expansion of macro 'lock_fini'
       lock_fini (dfa->lock);
       ^
regex_internal.h:77:26: error: statement with no effect [-Werror=unused-value]
 # define lock_fini(lock) 0
                          ^
regcomp.c:847:7: note: in expansion of macro 'lock_fini'
       lock_fini (dfa->lock);
       ^
In file included from regex.c:74:0:
regexec.c: In function 'rpl_regexec':
regexec.c:233:13: error: unused variable 'dfa' [-Werror=unused-variable]
   re_dfa_t *dfa = preg->buffer;
             ^
regexec.c: In function 're_search_stub':
regexec.c:424:13: error: unused variable 'dfa' [-Werror=unused-variable]
   re_dfa_t *dfa = bufp->buffer;
             ^
cc1: all warnings being treated as errors
make[4]: *** [regex.o] Error 1
make[4]: Leaving directory `/mnt/clfs/sources/tar/gnu'
make[3]: *** [all-recursive] Error 1
make[3]: Leaving directory `/mnt/clfs/sources/tar/gnu'
make[2]: *** [all] Error 2
make[2]: Leaving directory `/mnt/clfs/sources/tar/gnu'
make[1]: *** [all-recursive] Error 1
make[1]: Leaving directory `/mnt/clfs/sources/tar'
make: *** [all] Error 2

Sincerely,
王文鑫
Charlie