Autoconf has been deprecating configure.in for quite a long time.
Rename all our configure.in and preconfigure.in files to .ac.
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Pretty sure we require recent enough versions of gcc/binutils to make this
check pointless. I can't any logs in the last few years where this check
didn't return "yes".
Signed-off-by: Mike Frysinger <vapier@gentoo.org>