* ld-elfvsb/elfvsb.exp (support_protected): New variable. Check
and set to "yes" if the protected visibility is expected to
pass.
(visibility_run): Set expected to fail for the "protected"
and "protected_undef_def" tests only if $support_protected is
"no".
* ld-elfvsb/main.c (PROTECTED_CHECK): Check for the protected
visibility support if defined.