CMake tweak: include headers in targets

This improves navigation in XCode (any maybe some other tools)

CMakeModules/SimGearComponent.cmake

@@ -12,6 +12,11 @@ macro(simgear_component_common name includePath sourcesList sources headers)
 		set_property(GLOBAL
 			APPEND PROPERTY PUBLIC_HEADERS "${CMAKE_CURRENT_SOURCE_DIR}/${h}")
         set(fh${sourcesList} "${fh${sourcesList}}#${CMAKE_CURRENT_SOURCE_DIR}/${h}")
+
+        # also append headers to the sources list, so that IDEs find the files
+        # correctly (otherwise they are not in the project)
+        set_property(GLOBAL
+            APPEND PROPERTY ${sourcesList} "${CMAKE_CURRENT_SOURCE_DIR}/${h}")
 	endforeach()
 
     set_property(GLOBAL APPEND PROPERTY FG_GROUPS_${sourcesList}_C "${fc${sourcesList}}@")