[ng] rule, lang: get rid of 'suffix_rules_count', simplify logic
Apparently, some of our pre-existing logic used to determine when we need
to bring C-related stuff into the generated Makefile was too strict; we can
simplify it a bit, still keeping the testsuite clean.
* automake.in (handle_languages): Bring in C stuff only if we've seen a
non-pure language (like yacc or vala) or if '$need_link' is true, without
bothering to check whether we've seen more than one suffix rules. This
change removes the only caller in the automake code base of ...
* lib/Automake/Rule.pm (suffix_rules_count): ... this subroutine, which
has thus been removed.
(@EXPORT): Adjust.