commit-msg hook

[Eli Zaretskii]

On MS-Windows, this hook fails commits with valid UTF-8 characters in
the log messages, probably because the version of Gawk I have here is
too old (3.0.4; that's what MSYS comes with).

The mawk 1.3.3 replacement regexp for non_print does work, so I
suggest to have a Gawk version check in the script, and use the
replacement for older Gawk's.

Btw, when the hook is run by Git, the "; see 'CONTRIBUTE'" part of the
message is not shown; could it be that the semi-colon gets interpreted
by the shell, or something like that?  (My Git version is 1.9.5.)

I would also suggest to say explicitly in the message that the commit
was aborted, because it is not at all clear, at least to the
uninitiated.  It wasn't until I did a "git show" that the fact the
commit was aborted became apparent to me.

Thanks.