Fix TB

Include cassert and fix assert logical, we do want to have an handler here.

Following https://cgit.freedesktop.org/libreoffice/core/commit/?id=bca760c294c256fcb1fd3649dbf50f61a4bda474

Change-Id: I5ec7c399469a5674f0bc455fc3233c3421cc491f
Reviewed-on: https://gerrit.libreoffice.org/38933Reviewed-by: Julien Nabet <serval2412@yahoo.fr>
Tested-by: Julien Nabet <serval2412@yahoo.fr>

sal/osl/all/signalshared.cxx

@@ -17,6 +17,7 @@
  *   the License at http://www.apache.org/licenses/LICENSE-2.0 .
  */
 
+#include <cassert>
 #include <sal/config.h>
 
 #include <signalshared.hxx>
@@ -67,7 +68,7 @@ oslSignalAction callSignalHandler(oslSignalInfo* pInfo)
 
 oslSignalHandler SAL_CALL osl_addSignalHandler(oslSignalHandlerFunction handler, void* pData)
 {
-    assert(!handler);
+    assert(handler);
 
     if (!handler)
         return nullptr;
@@ -97,7 +98,7 @@ oslSignalHandler SAL_CALL osl_addSignalHandler(oslSignalHandlerFunction handler,
 
 sal_Bool SAL_CALL osl_removeSignalHandler(oslSignalHandler handler)
 {
-    assert(!handler);
+    assert(handler);
 
     if (!bInitSignal)
         bInitSignal = initSignal();