This supersedes commit 53c90158.

Signed-off-by: Felix Paul Kühne <fkuehne@videolan.org>

The whole point of keeping the m4 and po/Makefile.in.in is to not need
to have the same version all over the place anyway, otherwise we might
as well put all these files to .gitignore...

Remove some old m4 macros as well.

and fix the M4 ignore rules

This reverts commit 8b71b104.
Most developers did not update their gettext install
Bumping gettext requirement is useless.

* configure.ac.in, m4/*, po/Makefile.in.in: build updated to use gettext 0.11.5 by default.
   This is necessary for the win32 build because old gettext versions do not work on win32.

    always the same.