Ruby source main.c for AFL perf improvement

main.c

#undef RUBY_EXPORT
#include "ruby.h"
#include "vm_debug.h"
#ifdef HAVE_LOCALE_H
#include <locale.h>
#endif
#ifdef RUBY_DEBUG_ENV
#include <stdlib.h>
#endif

int
main(int argc, char **argv)
{
#ifdef RUBY_DEBUG_ENV
    ruby_set_debug_option(getenv("RUBY_DEBUG"));
#endif
#ifdef HAVE_LOCALE_H
    setlocale(LC_CTYPE, "");
#endif

    ruby_sysinit(&argc, &argv);
    RUBY_INIT_STACK;
    ruby_init();
    void *opts = ruby_options(argc, argv);
    #ifdef __AFL_HAVE_MANUAL_CONTROL
         __AFL_INIT();
    #endif
    return ruby_run_node(opts);
}