free_patternarg
free_patternarg(pattern);
static void free_patternarg(void *);
subst_mod = {get_spatternarg, NULL, VarSubstitute, free_patternarg},
resubst_mod = {get_patternarg, do_regex, NULL, free_patternarg},
sysv_mod = {get_sysvpattern, NULL, VarSYSVMatch, free_patternarg}