[Gm2] Gm2's search paths

[john o goyo]

I note that gcc can find its files from its location but gm2 cannot.
Specifically, if one renames the directory holding gcc, one can still 
invoke gcc without problems but gm2 cannot then find its definition files.

I learned this because before building a new version of gm2, I rename 
the directory holding the previous version and adjust build paths 
accordingly.  Gcc has no problem but gm2 cannot find system.def and so on.

Sincerely,
john