* cgraph.c (cgraph_node_cannot_be_local_p_1): Prevent targets of
	symver attributes to be localized.
	* ipa-visibility.c (cgraph_externally_visible_p,
	varpool_node::externally_visible_p): Likewise.
	* symtab.c (symtab_node::verify_base): Check visibility of symbol
	versions.

	* lto-common.c (read_cgraph_and_symbols): Work around binutils
	PR25424


Co-Authored-By: Xi Ruoyao <xry111@mengyan1223.wang>

From-SVN: r279566