* attribs.c (c_common_attribute_table): Add visibility.

	* attribs.c (c_common_attribute_table): Add visibility.
	(handle_visibility_attribute): New function.
	* varasm.c (assemble_visibility): New function.
	* output.h (assemble_visibility): Add prototype.
	* tree.h (MODULE_LOCAL_P): Define.
	* crtstuff.c (__dso_handle): Use visibility attribute.
	* config/i386/i386.h (ENCODE_SECTION_INFO): Set SYMBOL_REF_FLAG
	for MODULE_LOCAL_P symbols too.
	* config/ia64/ia64.c (ia64_encode_section_info): Handle
	MODULE_LOCAL_P symbols the same way as local symbols.
	Add SDATA_NAME_FLAG_CHAR even if decl was explicitely forced
	into .sdata/.sbss by the user.
	* doc/extend.texi (Function Attributes): Document visibility
	attribute.

	* gcc.dg/ia64-visibility-1.c: New test.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@50061 138bc75d-0d04-0410-961f-82ee72b054a4