Replace const_strneq with startswith.

Replace const_strneq with startswith.

binutils/ChangeLog:

	* dwarf.c (display_debug_lines_raw): Replace const_strneq with
	startswith.
	(display_debug_lines_decoded): Likewise.
	(display_debug_links): Likewise.
	* elfcomm.c (setup_archive): Likewise.
	* elfcomm.h (const_strneq): Likewise.
	* readelf.c (process_section_headers): Likewise.
	(slurp_ia64_unwind_table): Likewise.
	(slurp_hppa_unwind_table): Likewise.
	(decode_arm_unwind): Likewise.
	(display_debug_section): Likewise.
	(process_note): Likewise.