Jakub Jelinek  <jakub@redhat.com>
	
	PR libstdc++/19664 round 1
	* acinclude.m4 (GLIBCXX_ENABLE_VISIBILITY): Check it.
	* configure.ac: Use it.
	* configure: Regenerate.
	* docs/html/configopts.html: Document it.
	* include/Makefile.am: Slip in to c++config.
	* include/Makefile.in: Regenerate.
	* include/bits/c++config (_GLIBCXX_VISIBILITY): New.
	(_GLIBCXX_BEGIN_NAMESPACE): Use it.
	(_GLIBCXX_END_NAMESPACE): Use it.
	(_GLIBCXX_BEGIN_NESTED_NAMESPACE): Use it.
	(_GLIBCXX_END_NESTED_NAMESPACE): Use it.		
	* src/debug.cc: Mark __gnu_internal namespace with hidden
	visibility attribute.
	* src/ext-inst.cc: Same.
	* src/globals_io.cc: Same.
	* src/globals_locale.cc: Same.
	* src/ios_init.cc: Same.
	* src/locale.cc: Same.
	* src/mt_allocator.cc: Same.
	* src/pool_allocator.cc: Same.



git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@115632 138bc75d-0d04-0410-961f-82ee72b054a4