decl2.c (determine_visibility): Allow target to override visibility of class data.

decl2.c (determine_visibility): Allow target to override visibility of class data.

    gcc/cp/
    * decl2.c (determine_visibility): Allow target to override
    visibility of class data.

    gcc/
    * config/arm/arm.c (arm_cxx_determine_class_data_visibility): Make
    no-op for targets which don't use DLLs.

    gcc/testsuite/
    * g++.dg/ext/visibility/arm3.C: Add explanatory text. Skip on
    non-DLL targets.
    * g++.dg/ext/visibility/arm1.C: Skip on non-DLL targets.

Co-Authored-By: Mark Mitchell <mark@codesourcery.com>
From-SVN: r137922