Port varargs macros better to C99

Port varargs macros better to C99

C99 prohibits passing zero args to macro’s ‘...’.
* lib-src/seccomp-filter.c (RULE0): New macro, which is like RULE
except with zero args.  All zero-arg uses of RULE changed to RULE0.
* src/comp.c (compile_function, Fcomp__init_ctxt, syms_of_comp):
Change ‘CALLN (Fmake_hash_table)’ to ‘Fmake_hash_table (0, NULL)’,
since CALLN requires at least two args in C99.

(cherry picked from commit dd1efa5309d82139c6637e21ebd9eeb55e1814c1)