* script.cc (Version_script_info::get_versions): Don't add empty
version tag to return value.
(Version_script_info::get_symbol_version_helper): Change return
type to bool. Add pversion parameter. Change all callers.
(script_register_vers_node): Don't require a non-NULL tag.
* script.h (class Version_script_info): Update declarations.
(Version_script_info::get_symbol_version): Change return type to
bool. Add version parameter. Change all callers.
* symtab.cc (Sized_symbol::add_from_relobj): Rework version
handling. Handle an empty version from a version script.
(Symbol_table::define_special_symbol): Likewise.
* testsuite/ver_test_10.script: New file.
* testsuite/ver_test_10.sh: New file.
* testsuite/Makefile.am (check_SCRIPTS): Add ver_test_10.sh.
(check_DATA): Add ver_test_10.syms.
(ver_test_10.syms, ver_test_10.so): New target.
* testsuite/Makefile.in: Rebuild.
