Build environment updates

This pull contains commits to fix the OS X build and allow GitMake test to pass.
I said it worked because originally I wasn't using '-j', so it was working for me. When I used '-j 20', I didn't see the "cd: out.build: No such file or directory" errors and the shell return code was 0.

Perhaps try that on your end to verify; with the (now obsolete) change, it works, no errors. But then, it defeats the purpose of using '-j' to parallelize the build by breaking that case.

Yeah, I know -P doesn't change behavior; it's just interesting that it's not present in all version of bsdmake anymore, not even between versions of FreeBSD. :-)