The compiler is failing to build a couple of files which use rb_cFixnum types directly (cvchain.cpp and cvseq.cpp).

I tried changing the rb_cFixnums to rb_cIntegers, and it builds properly now. The test output is pretty spammy though, so I'm not sure if everything is working.

(Fixnums are still being used in the Ruby code, but it just throws lots of deprecation warnings).