tests: sniff for /usr/local/bin/gmake and use it in test-fuzz-targets.t
This isn't as robust as it probably should be, but for now it'll get
the job done on the buildbots.
Differential Revision: https://phab.mercurial-scm.org/D5269
Set up
$ hg init repo
$ cd repo
Try to import an empty patch
$ hg import --no-commit - <<EOF
> EOF
applying patch from stdin
abort: stdin: no diffs found
[255]
No dirstate backups are left behind
$ ls .hg/dirstate* | sort
.hg/dirstate