Explode if libgit2 or zlib are missing
Explode if libgit2 or zlib are missing

Makefile should not be created if one of these libraries
are missing.

Add proper checks and better message on failure.

libgit2/rugged,spraints/rugged,saraid/rugged,saraid/rugged,libgit2/rugged,tpickett66/rugged,spraints/rugged,tpickett66/rugged,Acidburn0zzz/rugged,saraid/rugged,Acidburn0zzz/rugged,Acidburn0zzz/rugged,tpickett66/rugged,libgit2/rugged