PR gold/12880

	PR gold/12880
	* layout.cc (Layout::attach_allocated_section_to_segment): Add a
	.interp section to a PT_INTERP segment even if we have seen a
	--dynamic-linker option.  Don't do it if we have seen a PHDRS
	clause in a linker script.
	(Layout::finalize): Don't create a .interp section if we've
	already create a PT_INTERP segment.
	(Layout::create_interp): Always call choose_output_section (revert
	patch of 2011-06-17).  Don't create PT_INTERP segment.
	* script-sections.cc
	(Script_sections::create_note_and_tls_segments): Add a .interp
	section to a PT_INTERP segment even if we have seen a
	--dynamic-linker option.