* cgraph.c (cgraph_release_function_body): Use used_as_abstract_origin.
	(cgraph_release_function_body): Likewise.
	(cgraph_can_remove_if_no_direct_calls_p): Likewise.
	* cgraph.h (cgrpah_node): Rename abstract_and_needed
	to used_as_abstract_origin.
	* tree-inline-transfrom.c (can_remove_node_now_p_1): Do not remove
	symbols used as abstract origins.
	* cgraphunit.c (analyze_functions): Update.
	* ipa.c (symtab_remove_unreachable_nodes): Recompute used_as_abstract_origin.
	* tree-inline.c (tree_function_versioning): Update
	used_as_abstract_origin; be ready for DECL_RESULT and DECL_ARGUMENTS to be
	NULL.

	* lto-symtab.c (lto_symtab_merge_symbols): Merge duplicated nodes for abstract functions.
	* cgraph.h (symtab_real_symbol_p): Abstract declarations are not real symbols.

From-SVN: r201408