update m4/ax_create_stdint_h.m4
update m4/ax_create_stdint_h.m4

In particular, update to the latest version from the autoconf archive,
but preserve the changes from 8c900e85d (ax_create_stdint_h.m4:
protect some limits from redefinition, Sat Sep 5 23:17:05 2009 +0200).

Signed-off-by: Sven Verdoolaege <235c10dd23b819f81cdc9756a251746bc184cab6@gmail.com>

Meinersbur/isl,Meinersbur/isl,Meinersbur/isl,Meinersbur/isl