use 'test_must_fail git cmd'. This will signal a failure if git
dies in an unexpected way (e.g. segfault).
+ On the other hand, don't use test_must_fail for running regular
+ platform commands; just use '! cmd'.
+
- use perl without spelling it as "$PERL_PATH". This is to help our
friends on Windows where the platform Perl often adds CR before
the end of line, and they bundle Git with a version of Perl that