ELF options may be missing from `ld --help' output

ELF options may be missing from `ld --help' output

nios2-linux has an emulation named "nios2linux", and happens to not include
another extra emulation with a name matching *elf*.  This makes nios2-linux
left out of the ELF options printing targets, which is unintended.

	* configure.ac (AC_PROG_GREP): Check for grep program.
	(elf_list_options,elf_shlib_list_options,elf_plt_unwind_list_options):
	Enable ELF option printing for emulations containing
	'TEMPLATE_NAME=elf32'.
	* configure: Regenerate.