RFC: add some static probes to libstdc++

[Jakub Jelinek]

On Thu, Feb 28, 2013 at 08:32:02AM -0700, Tom Tromey wrote:
> 2013-02-27  Tom Tromey  <tromey@redhat.com>
> 
> 	* libsupc++/unwind-cxx.h: Include sys/sdt.h if detected.
> 	(PROBE2): New macro.
> 	* libsupc++/eh_throw.cc (__cxa_throw, __cxa_rethrow): Add probe.
> 	* libsupc++/eh_catch.cc (__cxa_begin_catch): Add probe.
> 	* configure.ac: Check for sys/sdt.h.
> 	* configure, config.h.in: Rebuild.

This is ok.  As we are close to 4.8.0-rc1, I went ahead and committed it for
you.

	Jakub