lang-options.h: Add -fms-extensions.

	* lang-options.h: Add -fms-extensions.
	* cp-tree.h: Declare flag_ms_extensions.
	* decl2.c: Define it.
	* class.c (instantiate_type): Don't complain about taking the address
	of a bound member function if -fms-extensions.
	* typeck.c (build_unary_op): Likewise.
	* decl.c (grokdeclarator): Or about implicit int.
	* init.c (resolve_offset_ref): Or about implicit '&'.

From-SVN: r28684