A few compiling issues

I had a few issues compiling, and these commits fix them. I'm not sure if perhaps there was an issue on my end with GEANT versions w.r.t. -Werror (I used 4.9.6.p03), so maybe someone can confirm.
I'd like to keep `-Werror` if at all possible. If warnings are in non-RAT headers, we could use `-isystem` rather than `-I` for the include path to treat them as system headers.