Re: compress .gnu.debuglto_.debug_* sections if requested

Enable zlib-gnu compression for .gnu.debuglto_.debug_*.  This differs
from zlib-gnu for .debug_* where the name is changed to .zdebug_*.
The name change isn't really needed.

bfd/
	* elf.c (elf_fake_sections): Replace "." with ".z" in debug
	section names only when name was ".d*", ie. ".debug_*".
	(_bfd_elf_assign_file_positions_for_non_load): Likewise.
gas/
	* write.c (compress_debug): Compress .gnu.debuglto_.debug_*
	for zlib-gnu too.  Compress .gnu.linkonce.wi.*.