(LANGUAGES, COMPILERS, .PHONY, stmp-int-hdrs): Remove specific references to ObjC compiler and source files.

(LANGUAGES, COMPILERS, .PHONY, stmp-int-hdrs): Remove specific references to
ObjC compiler and source files.
({mostly,dist,maintainer,}clean, install-normal): Likewise
(OBJC_OBJS, OBJC, OBJECTIVE-C, cc1obj, objc-runtime): Rules deleted.
(libobjc.a, sublibobjc.a, objc-parse.{o, c, y}): Rules deleted.
(objc-headers, install-libobjc): Rules deleted.

From-SVN: r14281