libgfortran's generated files uses the wrong automake version (was: [PATCH 21/22] Coarray caf_shmem final patch set)

Hi Jerry,

your commit

r16-7742-gd3357082baa832  Regenerate autoconf/automake files.

has:

--- a/libgfortran/Makefile.in
+++ b/libgfortran/Makefile.in
@@ -1,7 +1,7 @@
-# Makefile.in generated by automake 1.15.1 from Makefile.am.
+# Makefile.in generated by automake 1.18.1 from Makefile.am.

...

https://gcc.gnu.org/install/prerequisites.html#Tools_002fpackages-necessary-for-modifying-GCC

states the required versions:

* autoconf version 2.69
* automake version 1.15.1

The idea is that everyone uses the same version - such that the generated files
only contain the respective changes and not a flip flop between different versions.

For other files, the exact version does no matter (noted with '(or later)')

Can you fix it?

Tobias