[PATCH] gold, dwp: support zstd compressed input debug sections [PR 29641]

[Cary Coutant]

>  elfcpp/elfcpp.h                         |   1 +
>  gold/Makefile.am                        |  10 +-
>  gold/Makefile.in                        |  16 +-
>  gold/aclocal.m4                         |   1 +
>  gold/compressed_output.cc               |  44 ++--
>  gold/config.in                          |   3 +
>  gold/configure                          | 258 +++++++++++++++++++++++-
>  gold/configure.ac                       |   3 +-
>  gold/testsuite/Makefile.am              |  17 +-
>  gold/testsuite/Makefile.in              |  32 ++-
>  gold/testsuite/gdb_index_test_2_zstd.sh |  24 +++
>  11 files changed, 361 insertions(+), 48 deletions(-)
>  create mode 100755 gold/testsuite/gdb_index_test_2_zstd.sh

In testsuite/Makefile.am:

@@ -3120,6 +3120,15 @@ gdb_index_test_2_gabi:
gdb_index_test_cdebug_gabi.o gcctestdir/ld
        $(CXXLINK) -Wl,--gdb-index $<
 gdb_index_test_2_gabi.stdout: gdb_index_test_2_gabi
        $(TEST_READELF) --debug-dump=gdb_index $< > $@
+check_SCRIPTS += gdb_index_test_2_zstd.sh
+check_DATA += gdb_index_test_2_zstd.stdout
+MOSTLYCLEANFILES += gdb_index_test_2_zstd.stdout gdb_index_test_2_zstd
+gdb_index_test_cdebug_zstd.o: gdb_index_test.cc
+       $(CXXCOMPILE) -O0 -g -Wa,--compress-debug-sections=zstd -c -o $@ $<
+gdb_index_test_2_zstd: gdb_index_test_cdebug_zstd.o gcctestdir/ld
+       $(CXXLINK) -Wl,--gdb-index $<
+gdb_index_test_2_zstd.stdout: gdb_index_test_2_zstd
+       $(TEST_READELF) --debug-dump=gdb_index $< > $@

These new tests should be conditioned on HAVE_ZSTD, right?

Otherwise, looks good to me. Thanks!

-cary