Since the code is identical when just checking if a utility is present on
the system or not, we can factorize it.
Signed-off-by: Quentin Casasnovas <quentin.casasnovas@oracle.com>
* src/patch.c (main): Generate the "patching file" message here. When
the input and output file name is not he same, include both names in
the message.
* src/inp.c (scan_input): Previously the "patching file" message was
generated here.
* tests/unmodified-files, tests/copy-rename: Update.
* tests/test-lib.sh: Flag tests with missing pre-requirements as
SKIPped instead of PASSed. Do not use GNU diff extensions, but
still require a diff that understands "-u".
* tests: Do not unnecessarily require GNU diff in a lot of tests.
Make the sed utility optional.
