Qt6 migration fixes: RTI DDS alias targets, ErrorMessage namespace, DDS header include path

qt6-after/qt6-migrated-legatus/Lts/Application/THP/SitMapReplayTest/CMakeLists.txt

@@ -17,7 +17,7 @@ NGL_ADD_EXECUTABLE(WS SitMapReplayTest ${SRPTEST_SRCS})
 NGL_TARGET_LINK_LIBRARIES(SitMapReplayTest
   SituationReplaySqlite
 
-  ddsconnector
+  $<IF:$<TARGET_EXISTS:ddsconnector>,ddsconnector,>
   Qt6::Core
   nglapplication
   SitmapDds
@@ -33,7 +33,7 @@ NGL_TARGET_LINK_LIBRARIES(SitMapReplayTest
   svcBldClient
   svcCesClient
   svcGimClient
-  svcIsmClient
+  $<IF:$<TARGET_EXISTS:svcIsmClient>,svcIsmClient,>
   svcPpmClient
   svcPdmClient
 )

qt6-after/qt6-migrated-legatus/Lts/Application/THP/SitMapReplayTest/srp_main_window.h

@@ -8,7 +8,7 @@
   */
 #pragma once
 
-#include <QMainWindow>
+#include <QtWidgets/QMainWindow>
 #include <memory>
 
 namespace Ui