Add ld_list_options

Add ld_list_options

This patch adds ld_list_options for ELF targets to avoid duplicated
outputs from ld --help.

	* Makefile.am (ELF_CLFAGS): New.
	(AM_CFLAGS): Add $(ELF_CLFAGS).
	* configure.ac (elf_list_options): New.  AC_SUBST.
	(elf_shlib_list_options): Likewise.
	(elf_plt_unwind_list_options): Likewise.
	* lexsup.c (elf_shlib_list_options): New.
	(elf_static_list_options): Likewise.
	(elf_plt_unwind_list_options): Likewise.
	(ld_list_options): Likewise.
	(help): Call ld_list_options.
	* Makefile.in: Regenerated.
	* configure: Likewise.
	* emulparams/plt_unwind.sh (PLT_UNWIND): New.
	(PARSE_AND_LIST_OPTIONS): Removed.
	* emultempl/elf32.em (gld_list_options): New.
	(gld${EMULATION_NAME}_list_options): Define only if BNDPLT or
	PARSE_AND_LIST_OPTIONS is defined.
	(ld_${EMULATION_NAME}_emulation): Replace
	gld${EMULATION_NAME}_list_options with ${gld_list_options.