Jan D. wrote:
> It keeps complaining about control caracter, even if there are none....
> Does it assume GNU awk?

No, it assumes only POSIX awk.  However, it turns out that FreeBSD awk is buggy 
here; see FreeBSD bug#195792 <http://bugs.freebsd.org/195792>.

I worked around the FreeBSD bug by installing the attached patch to the emacs-24 
branch; this should be merged into the Emacs master in due course.  After 
applying the patch, you can run './autogen.sh' to propagate the fix into your 
.git/hooks/commit-msg.