* config/darwin-protos.h (darwin_assemble_visibility): Declare.
	* config/darwin.c (darwin_assemble_visibility): Define.  Warn for
	anything other than VISIBILITY_DEFAULT and VISIBILITY_HIDDEN.
	* config/darwin.h (TARGET_ASM_ASSEMBLE_VISIBILITY): Use
	darwin_assemble_visibility instead of default.

From-SVN: r73430