[gold][PATCH] Extend --compress-debug-sections in gold

[Cary Coutant]

> This patch extends --compress-debug-sections= with [zlib-gnu|zlib-gabi]
> in gold.
>
>         PR gold/18322
>         * compressed_output.cc (zlib_compress): Add argument for
>         compression header size.  Set header size to compression header
>         size if it isn't 0.  Don't write out the zlib header here.
>         (Output_compressed_section::set_final_data_size): Support
>         zlib-gnu and zlib-gabi compressions.  Pass compression header
>         size to zlib_compress and write out compression header.  Set
>         the SHF_COMPRESSED bit for zlib-gabi compression.  Otherwise
>         clear the SHF_COMPRESSED bit
>         * options.h (compress_debug_sections): Add zlib-gnu and
>         zlib-gabi.
>         * output.h (Output_section::set_flags): New.
>         * testsuite/Makefile.am (check_PROGRAMS): Add
>         flagstest_compress_debug_sections_none,
>         flagstest_compress_debug_sections_gnu and
>         flagstest_compress_debug_sections_gabi.
>         (check_DATA): Add flagstest_compress_debug_sections_none.stdout.
>         flagstest_compress_debug_sections.stdout,
>         flagstest_compress_debug_sections.cmp,
>         flagstest_compress_debug_sections.check,
>         flagstest_compress_debug_sections_gnu.stdout,
>         flagstest_compress_debug_sections_gnu.cmp,
>         flagstest_compress_debug_sections_gnu.check,
>         flagstest_compress_debug_sections_gabi.stdout,
>         flagstest_compress_debug_sections_gabi.cmp and
>         flagstest_compress_debug_sections_gabi.check.
>         (flagstest_compress_debug_sections_none): New.
>         (flagstest_compress_debug_sections_none.stdout): Likewise.
>         (flagstest_compress_debug_sections.stdout): Likewise.
>         (flagstest_compress_debug_sections.check): Likewise.
>         (flagstest_compress_debug_sections.cmp): Likewise.
>         (flagstest_compress_debug_sections_gnu): Likewise.
>         (flagstest_compress_debug_sections_gnu.stdout): Likewise.
>         (flagstest_compress_debug_sections_gnu.check): Likewise.
>         (flagstest_compress_debug_sections_gnu.cmp): Likewise.
>         (flagstest_compress_debug_sections_gabi): Likewise.
>         (flagstest_compress_debug_sections_gabi.stdout): Likewise.
>         (flagstest_compress_debug_sections_gnu.check): Likewise.
>         (flagstest_compress_debug_sections_gnu.cmp): Likewise.
>         * testsuite/Makefile.in: Regenerated.

This is OK. Thanks!

-cary