* configure.in: Add AM_PROG_CC_C_O to work around problems with some
compilers.

* aclocal.m4: Regenerated.
* Makefile.in: Ditto.
* config.h.in: Ditto.
* configure: Ditto.
(Thanks to Stephen Cameron <smcameron@yahoo.com> and
Tom Tromey <tromey@redhat.com>.)