* doc/autoconf.texi (Generating Sources): AC_LANG_PROGRAMS ->
AC_LANG_PROGRAM, fixing a typo. Don't give details about
the inner workings of AC_LANG_FUNC_LINK_TRY.
* lib/autoconf/c.m4 (AC_LANG_CALL(C)): Reformat to match
AC_LANG_FUNC_LINK_TRY. This involves returning the value returned
by the function rather than ignoring it.
(AC_LANG_FUNC_LINK_TRY(C)): Call the function rather than simply
comparing its address. Intel's interprocedural optimization was
outsmarting the old heuristic. Problem reported by
Mikulas Patocka.