Fix --gc-sections failure with symbol versioning.

Fix --gc-sections failure with symbol versioning.

bfd/

2011-09-28  H.J. Lu  <hongjiu.lu@intel.com>

	PR ld/13195
	* elflink.c (_bfd_elf_merge_symbol): Don't set dynamic_def when
	clearing def_dynamic.
	(elf_link_add_object_symbols): Likewise.  Set dynamic_def when
	setting def_dynamic.
	(bfd_elf_gc_mark_dynamic_ref_symbol): Check if a symbol is
	versioned.

ld/testsuite/

2011-09-28  H.J. Lu  <hongjiu.lu@intel.com>

	PR ld/13195
	* ld-elf/elf.exp: Add a C link testcase for PR ld/13195.

	* ld-elf/pr13195.c: New.
	* ld-elf/pr13195.d: Likewise.
	* ld-elf/pr13195.s: Likewise.
	* ld-elf/pr13195.t: Likewise.