* gc.h (Garbage_collection::Cident_section_map): New typedef.

	* gc.h (Garbage_collection::Cident_section_map): New typedef.
	(Garbage_collection::cident_sections): New function.
	(Garbage_collection::add_cident_section): New function.
	(Garbage_collection::cident_sections_): New member.
	(gc_process_relocs): Add references to sections whose names are C
	identifiers.
	* gold.h (cident_section_start_prefix): New constant.
	(cident_section_stop_prefix): New constant.
	(is_cident): New function.
	* layout.cc (Layout::define_section_symbols): Replace string constants
	with the newly defined constants.
	* object.cc (Sized_relobj::do_layout): Track sections whose names are
	C identifiers.
	* testsuite/Makefile.am: Add gc_orphan_section_test.
	* testsuite/Makefile.in: Regenerate.
	* testsuite/gc_orphan_section_test.cc: New file.
	* testsuite/gc_orphan_section_test.sh: New file.