* symtab.cc (Symbol_table::add_from_object): If the visibility is
hidden or internal, force the symbol to be local.
* resolve.cc (Symbol::override_visibility): Define.
(Symbol::override_base): Use override_visibility.
(Symbol_table::resolve): Likewise.
(Symbol::override_base_with_special): Likewise.
(Symbol_table::override_with_special): If the visibility is hidden
or internal, force the symbol to be local.
* symtab.h (class Symbol): Add set_visibility and
override_visibility.
* testsuite/ver_test_1.sh: New file.
* testsuite/Makefile.am (check_SCRIPTS): Add ver_test_1.sh.
(check_DATA): Add ver_test_1.syms.
(ver_test_1.syms): New target.
* testsuite/Makefile.in: Rebuild.
