Work around a Clang trunk (towards 3.6) -Werror,-Wunused-value

Change-Id: I3ee32c5bd379bb851f8f255faa93d96227dcff84
diff --git a/tools/source/debug/debug.cxx b/tools/source/debug/debug.cxx
index 9e65c44..093622e 100644
--- a/tools/source/debug/debug.cxx
+++ b/tools/source/debug/debug.cxx
@@ -324,7 +324,20 @@ TOOLS_DLLPUBLIC void DbgUnhandledException(const css::uno::Any & caught, const c
        }
        if ( exception.Context.is() )
        {
#if defined __clang__
#if __has_warning("-Wunused-value")
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wunused-value"
    // "expression with side effects will be evaluated despite being used as an
    // operand to 'typeid'"
#endif
#endif
            const char* pContext = typeid( *exception.Context.get() ).name();
#if defined __clang__
#if __has_warning("-Wunused-value")
#pragma GCC diagnostic pop
#endif
#endif
            sMessage += "\ncontext: ";
            sMessage += pContext;
        }