PR libobjc/13946
	* Makefile.def: Add dependencies for libobjc which boehm-gc.
	* Makefile.in: Regenerate.
	* configure.in: Add --enable-objc-gc at toplevel and have it
	enable boehm-gc for Objective-C.
	Remove target-boehm-gc from libgcj.
	Add target-boehm-gc to target_libraries.
	Add target-boehm-gc to noconfigdirs where ${libgcj}
	is specified.
	Assert that boehm-gc is supported when requested for Objective-C.
	Only build boehm-gc if needed either for Java or Objective-C.
	* configure: Regenerate.
	


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@114435 138bc75d-0d04-0410-961f-82ee72b054a4