build: avoid touching .po files during 'make'

A simple workaround to deal with GNU gettext automake integration
failing to deal with git.

Reviewed-by: Neil Roberts <neil@linux.intel.com>

autogen.sh

@@ -16,6 +16,10 @@ test $TEST_TYPE $FILE || {
 	exit 1
 }
 
+# GNU gettext automake support doesn't get along with git.
+# https://bugzilla.gnome.org/show_bug.cgi?id=661128
+touch -t 200001010000 po/cogl.pot
+
 if automake-1.11 --version < /dev/null > /dev/null 2>&1 ; then
     AUTOMAKE=automake-1.11
     ACLOCAL=aclocal-1.11