Fixes for automake and autogen.sh in Debian testing

Remove automake macros obsoleted by automake 1.13. Fixes #9324.
(cherry-pick mono/master commit: 052ba601f3)
Fix the check for autoheader in autogen.sh.
(cherry-pick mono/master commit: e63ddd2450)
Fix the check for autoheader in eglib/autogen.sh and libgc/autogen.sh
too.
(cherry-pick mono/master commit: 2cde8a7269)

Change-Id: Iffe17522d5d194b93fab503876b87ada3a9a7604