Executable files in Windows need to have the extension '.exe', otherwise
they do not work. Extend the hooks to not just look at the hard coded
names, but also at the names extended by the custom STRIP_EXTENSION,
which is defined as '.exe' in Windows.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>