remove deprecated defines

- PERL_STATIC_LIBS (was not tested anymore)
- HAVE_GMODULE (always required)
- HAVE_STATIC_IRC
- HAVE_STATIC_PERL
- HAVE_SOCKS (was not working properly)
- USE_GREGEX (we use it)

src/fe-common/irc/meson.build

@@ -20,8 +20,6 @@ libfe_common_irc_a = static_library('fe_common_irc',
     'fe-whois.c',
     'irc-completion.c',
     'module-formats.c',
-
-    'irc-modules.c',
   ),
   include_directories : rootinc,
   implicit_include_directories : false,