<https://llvm.org/bugs/show_bug.cgi?id=12255> "with -fvisibility-inlines-hidden
needed copy not emitted for virtual inline function" (which covers the relevant
part of the Clang bug 11250 mentioned in the check) is reportedly fixed ever
since at last Clang 3.2.

Make this a fatal configure error for now.  The check should be removed
completely after LO 5.3 branch-off.

Change-Id: I47edf92968f32735a509ef649e0e85b891baab4b
Reviewed-on: https://gerrit.libreoffice.org/29074Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Stephan Bergmann <sbergman@redhat.com>