[gold patch] Fix internal error with --start-lib and object file with no global syms

[Cary Coutant <ccoutant at google dot com>]

If gold encounters an object file between --start-lib and --end-lib
that has no global symbols, it will trigger an assertion failure due
to a failure to lock the file before destroying the views in that
file. This patch fixes that problem and tweaks the --start-lib test
case to trigger the problem.

OK?

-cary

        * archive.cc (Lib_group::add_symbols): Lock object before deleting its
        symbols data.
        (Lib_group::include_member): Unlock object after deleting its
        symbols data.
        * testsuite/start_lib_test_3.c: Remove all global symbols to trigger
        the bug fixed here.

Attachment: gold-start-lib-lock-patch.txt
Description: Text document