re PR libstdc++/34680 (Unconditional use of dynamic_cast in locale_facets.tcc breaks compilation with -fno-rtti)

gcc/
2008-01-06  Paolo Carlini  <pcarlini@suse.de>

	PR libstdc++/34680
	* c-cppbuiltin.c (c_cpp_builtins): Define __GXX_RTTI, if appropriate.
	* doc/cpp.texi ([Common Predefined Macros]): Document.

gcc/testsuite/
2008-01-06  Paolo Carlini  <pcarlini@suse.de>

	PR libstdc++/34680
	* g++.dg/rtti/predefined-rtti-macro-1.C: New.
	* g++.dg/rtti/predefined-rtti-macro-2.C: Likewise.

From-SVN: r131366