Fix C++ build problems introduced in 9a5a5549

Fix C++ build problems introduced in 9a5a5549

Fixes the following compilation errors:
regexec.c: In function 'char* S_find_byclass(regexp*, const regnode*, char*,
const char*, regmatch_info*)':
regexec.c:1525: error: invalid conversion from 'I32 (*)(const char*, const
char*, I32)' to 'I32 (*)()'
regexec.c:1525: error: too many arguments to function
regexec.c:1527: error: invalid conversion from 'I32 (*)(const char*, const
char*, I32)' to 'I32 (*)()'
regexec.c:1527: error: too many arguments to function