"gcc -o conftest.exe -I/usr/include/ruby-2.2.0 -I/usr/include/ruby-2.2.0/ruby/backward -I/usr/include/ruby-2.2.0 -I.    -ggdb -O2 -pipe -Wimplicit-function-declaration    conftest.c  -L. -L/usr/lib -L. -fstack-protector     -lruby220  -lpthread -lgmp -ldl -lcrypt   "
checked program was:
/* begin */
1: #include "ruby.h"
2:
3: int main(int argc, char **argv)
4: {
5:   return 0;
6: }
/* end */