patch: warn when the internal patcher fails
hopefully we'll soon fix the remaining failures from the internal patcher, and
not use the external one anymore.
run-tests: make sure GREP_OPTIONS isn't set
This can interfere with test output, especially for options like --color.
patch: more precise NoHunk, raised for every file (
issue2102)
patch: try harder to find the file to patch on file creation (
issue2041)
accept the following patch header:
first line: foo/a.orig
second line: foo/a