Related: fdo#66440 RTF export: handle NULL component in FlyFrameOLEMath()

No testcase, for some reason the bugdoc doesn't crash in
CppunitTest_sw_filters_test, but it does using './soffice --headless
--convert-to'. But anyway, it's just a NULL pointer check.

Change-Id: I21325a4df45b3b9bcd43d0a8eb57d45b3ab7397c

sw/source/filter/ww8/rtfattributeoutput.cxx

@@ -3558,6 +3558,8 @@ bool RtfAttributeOutput::FlyFrameOLEMath(const SwFlyFrmFmt* pFlyFrmFmt, SwOLENod
 
     m_aRunText->append("{" LO_STRING_SVTOOLS_RTF_MMATH " ");
     uno::Reference<util::XCloseable> xClosable(xObj->getComponent(), uno::UNO_QUERY);
+    if (!xClosable.is())
+        return false;
 // gcc4.4 (and 4.3 and possibly older) have a problem with dynamic_cast directly to the target class,
 // so help it with an intermediate cast. I'm not sure what exactly the problem is, seems to be unrelated
 // to RTLD_GLOBAL, so most probably a gcc bug.