[yocto] Fix prelink build with automake-1.13

[Marko Lindqvist]

[PATCH] fix build with automake-1.13.

Long obsolete AM_CONFIG_HEADER is completely removed from automake-1.13,
which errors out upon seeing it.
configure.in -> configure.ac rename is not strictly necessary yet,
use of deprecated name still gives only warning.

Problem in dropping obsolete constructs is that support for autotools
versions so ancient that now-obsolete way is the only way to do things.
configure.in seems to have AC_PREREQ(2.13), but with these changes
(if not earlier) such an ancient autoconf will not do.


 - ML