bfd/

bfd/
	* xcofflink.c (xcoff_mark_symbol_by_name): New function.
	(bfd_xcoff_size_dynamic_sections): Use it to mark the entry,
	init and fini functions.  Do garbage collection for objects
	without an entry point too.

ld/testsuite/
	* ld-powerpc/aix-gc-1.s, ld-powerpc/aix-gc-1.ex,
	ld-powerpc/aix-gc-1-32.dd, ld-powerpc/aix-gc-1-64.dd,
	ld-powerpc/aix-weak-1-gcdso.dnd, ld-powerpc/aix-weak-1-gcdso.hd,
	ld-powerpc/aix-weak-1-gcdso.nd: New tests.
	* ld-powerpc/aix52.exp: Run them.