fix Windows build

after commit 22b094f5d8e1e82375b135abd3a6f99a9a555244
"loplugin:unusedmethods basic"

Change-Id: I7586d2487e47731db93335c3d9969626bf2eb6ab
diff --git a/basic/source/runtime/dllmgr-x64.cxx b/basic/source/runtime/dllmgr-x64.cxx
index 90b2094..d71d9d8 100644
--- a/basic/source/runtime/dllmgr-x64.cxx
+++ b/basic/source/runtime/dllmgr-x64.cxx
@@ -311,7 +311,7 @@ SbError marshal(
            case SbxDOUBLE:
            case SbxBOOL:
            case SbxBYTE:
                add(blob, variable->data(), 8, offset);
                add(blob, variable->GetValues_Impl(), 8, offset);
                break;
            case SbxSTRING:
                {