PR-108373 Update contrib/gcc_update:files_and_dependencies for Modula-2

This patch adds the dependencies for automatically generated files used
by the Modula-2 front end.

contrib/ChangeLog:

	* gcc_update (files_and_dependencies): Add dependencies for
	gcc/m2/gm2config.h.in, gcc/m2/configure,
	gcc/m2/gm2-libs/config-host, libgm2/Makefile.in,
	libgm2/aclocal.m4, libgm2/libm2cor/Makefile.in,
	libgm2/libm2pim/Makefile.in, libgm2/libm2iso/Makefile.in,
	libgm2/libm2log/Makefile.in and libgm2/libm2min/Makefile.in.

Signed-off-by: Gaius Mulley <gaiusmod2@gmail.com>