autotools.bbclass: Fix gettext macro versions issues

autotools.bbclass: Fix gettext macro versions issues

gettext m4 macros don't use the usual versioning/serial mechanism used by
aclocal. It therefore won't update them over and above any local version of
the macro. Equally, we don't run gettextize due to it doing slightly crazy
things to the build.

When we put the aclocal directory as a -I option to aclocal, if this was
found first compared to any recipe provided macros, the correct version
of the gettext macro would still "win". With the switch so correctly override
the system directory, older recipe provided macros may get used.

This patch manually removes the problematic m4 macros in the case we're using
gettext and need to use the correct m4 macros.

This patch also always ensures the gettext manipulations happen, even in the
-native case since missing or stale gettext files could cause build failures.

(From OE-Core rev: e9645d2bbeabaa5251d49edd659ab320fd66d0ee)

(From OE-Core rev: 841ea3c1c18e50e77fccbd5f44d6a79a50913b67)

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>