* libc/include/machine/_default_types.h: Move extern "C" after
	header includes.  Include <sys/features.h> for
	__GNUC_PREREQ__().
	(__u?int.*_t): Define via GCC provided __U?INT.*_TYPE__ if
	available.
	(__intptr_t): Define.
	(__uintptr_t): Likewise.
	* libc/include/stdint.h: Include <machine/_default_types.h>
	instead of <_ansi.h>.
	(u?int.*_t): Define via __u?int.*_t provided by
	<machine/_default_types.h>.
	(u?int_fast.*_t): Define via GCC provided
	__U?INT_FAST.*_TYPE__ if available.
	(U?INT.*(MIN|MAX)): Define via GCC provided __U?INT.*(MIN|MAX)__
	if available.
	(U?INT.*_C): Define via GCC provided __U?INT.*_C if available.
	* libc/include/sys/cdefs.h: Use <machine/_default_types.h>
	instead of <stdint.h>.
	* libc/sys/rtems/sys/cpuset.h: Likewise.
	* libc/sys/rtems/machine/_types.h: Include <stdint.h> for
	FreeBSD compatibility.
	* libc/sys/rtems/sys/cpuset.h: Use __inline instead of inline.
* configure.ac: Don't require 64-bit compiler for 32-bit builds.
* configure: Regenerate.
* select.cc (select): Add workaround for, as yet undebugged, pathological case.
* configure.ac: Back out stupid change.
* configure: Regenerate.