* invoke.texi: Document more C++ command-line options.

	Remove support for -Wextern-inline, -flabels-ok, -fvtable-gc, -fxref
	* cp-tree.h (warn_extern_inline): Remove.
	(flag_labels_ok): Likewise.
	* decl2.c (warn_extern_inline): Remove.
	(flag_labels_ok): Likewise.
	(lang_f_options): Remove labels-ok, vtable-gc, xref.
	(unsupported_options): Add them.
	(cxx_decode_option): Don't accept -Wextern-inline.
	* method.c (hack_identifier): Remove -flabels-ok support.
	* spew.c (see_typename): Likewise.

	* g++.dg/vtgc1.C: XFAIL.
	* g++.old-deja/g++.other/crash18.C: Likewise.

From-SVN: r41609