Export Target fixes for better transitive properties

CMakeLists.txt

@@ -92,6 +92,7 @@ ENDIF()
 
 PROJECT(osgQt)
 
+INCLUDE(GNUInstallDirs)
 FIND_PACKAGE(OpenSceneGraph 3.6.0 REQUIRED osgDB osgGA osgUtil osgText osgViewer osgWidget)
 SET(OPENSCENEGRAPH_SOVERSION 145)
 

osgQOpenGLConfig.cmake.in

@@ -1,2 +1,24 @@
+if(TARGET osg-qt::osgQOpenGL)
+    set(_OSGQOPENGL_ALREADY_DEFINED ON)
+endif()
+
 include(CMakeFindDependencyMacro)
-include("${CMAKE_CURRENT_LIST_DIR}/osg-qtTargets.cmake") 
+
+if(NOT TARGET Qt5::OpenGL)
+    find_dependency(Qt5 COMPONENTS Gui OpenGL REQUIRED)
+endif()
+# Instead of checking OPENSCENEGRAPH_LIBRARIES, check osgViewer and osgUtil specifically
+if(NOT DEFINED OSGUTIL_LIBRARIES OR NOT DEFINED OSGVIEWER_LIBRARIES OR NOT DEFINED OPENSCENEGRAPH_INCLUDE_DIRS)
+    find_dependency(OpenSceneGraph COMPONENTS osgUtil osgViewer REQUIRED)
+endif()
+
+include("${CMAKE_CURRENT_LIST_DIR}/osg-qtTargets.cmake")
+
+if(NOT _OSGQOPENGL_ALREADY_DEFINED)
+    # Replace the interface link libraries with those found by OSG, to allow this to be more easily relocatable.
+    # Without this, absolute paths to OSG are stored in the target, making the output library non-relocatable
+    # to other machines unless they have OSG in the exact same location.
+    set_target_properties(osg-qt::osgQOpenGL PROPERTIES INTERFACE_LINK_LIBRARIES "Qt5::Widgets;Qt5::OpenGL")
+    target_link_libraries(osg-qt::osgQOpenGL INTERFACE ${OPENSCENEGRAPH_LIBRARIES})
+    target_include_directories(osg-qt::osgQOpenGL INTERFACE ${OPENSCENEGRAPH_INCLUDE_DIRS})
+endif()

src/osgQOpenGL/CMakeLists.txt

@@ -50,6 +50,7 @@ IF ( Qt5Widgets_FOUND )
 
     SETUP_LIBRARY(${LIB_NAME})
 
+    target_include_directories(${LIB_NAME} PUBLIC $<INSTALL_INTERFACE:include>)
     generate_export_header(${LIB_NAME} EXPORT_FILE_NAME "Export")
 
 ENDIF()