ld * ld.h (struct ld_config_type): Add new field: warn_orphan.
* ldlex.h (enum option_values): Add OPTION_WARN_ORPHAN and
OPTION_NO_WARN_ORPHAN.
* lexsup.c (ld_options): Add --warn-orphan and --no-warn-orphan.
(parse_args): Handle the new options.
* ldemul.c (ldemul_place_orphan): If requested, generate a warning
message when an orphan section is placed in the output file.
* ld.texinfo: Document the new option.
* NEWS: Mention the new feature.
tests * ld-elf/orphan-5.l: New test - checks the linker's output with
--warn-orphan enabled.
* ld-elf/elf.exp: Run the new test.
