fix building and packaging issue with macos and qt plugins, they do not yet support versionless as it is a problem with cmake

CMakeLists.txt

@@ -236,14 +236,13 @@ find_package(OpenGL REQUIRED)
 find_package(LZ4 REQUIRED)
 
 if (USE_QT)
-	find_package(Qt5 5.15 COMPONENTS Core Widgets Network OpenGL)
-	if (Qt5_FOUND)
-		message(STATUS "Using Qt5")
+    find_package(QT REQUIRED COMPONENTS Core NAMES Qt6 Qt5)
+	if (QT_VERSION_MAJOR VERSION_EQUAL 5)
+        find_package(Qt5 5.15 COMPONENTS Core Widgets Network OpenGL REQUIRED)
 	else()
-		find_package(Qt6 6.4 COMPONENTS Core Widgets Network OpenGL REQUIRED)
-		message(STATUS "Using Qt6")
-		message(STATUS "Warning: Qt6 support is experimental and incomplete")
-	endif()
+		find_package(Qt6 COMPONENTS Core Widgets Network OpenGL REQUIRED)
+    endif()
+    message(STATUS "Using Qt${QT_VERSION}")
 endif()
 
 set(USED_OSG_COMPONENTS
@@ -819,13 +818,13 @@ if (OPENMW_OSX_DEPLOYMENT AND APPLE)
         message(FATAL_ERROR "macOS packaging requires CMake 3.19 or higher to sign macOS app bundles.")
     endif ()
 
-    get_property(QT_COCOA_PLUGIN_PATH TARGET Qt::QCocoaIntegrationPlugin PROPERTY LOCATION_RELEASE)
+    get_property(QT_COCOA_PLUGIN_PATH TARGET Qt${QT_VERSION_MAJOR}::QCocoaIntegrationPlugin PROPERTY LOCATION_RELEASE)
     get_filename_component(QT_COCOA_PLUGIN_DIR "${QT_COCOA_PLUGIN_PATH}" DIRECTORY)
     get_filename_component(QT_COCOA_PLUGIN_GROUP "${QT_COCOA_PLUGIN_DIR}" NAME)
     get_filename_component(QT_COCOA_PLUGIN_NAME "${QT_COCOA_PLUGIN_PATH}" NAME)
     configure_file("${QT_COCOA_PLUGIN_PATH}" "${APP_BUNDLE_DIR}/Contents/PlugIns/${QT_COCOA_PLUGIN_GROUP}/${QT_COCOA_PLUGIN_NAME}" COPYONLY)
 
-    get_property(QT_QMACSTYLE_PLUGIN_PATH TARGET Qt::QMacStylePlugin PROPERTY LOCATION_RELEASE)
+    get_property(QT_QMACSTYLE_PLUGIN_PATH TARGET Qt${QT_VERSION_MAJOR}::QMacStylePlugin PROPERTY LOCATION_RELEASE)
     get_filename_component(QT_QMACSTYLE_PLUGIN_DIR "${QT_QMACSTYLE_PLUGIN_PATH}" DIRECTORY)
     get_filename_component(QT_QMACSTYLE_PLUGIN_GROUP "${QT_QMACSTYLE_PLUGIN_DIR}" NAME)
     get_filename_component(QT_QMACSTYLE_PLUGIN_NAME "${QT_QMACSTYLE_PLUGIN_PATH}" NAME)

extern/osgQt/CMakeLists.txt

@@ -8,7 +8,7 @@ set(OSGQT_SOURCE_FILES
 
 add_library(${OSGQT_LIBRARY} STATIC ${OSGQT_SOURCE_FILES})
 
-target_link_libraries(${OSGQT_LIBRARY} Qt5::Core Qt5::OpenGL)
+target_link_libraries(${OSGQT_LIBRARY} Qt::Core Qt::OpenGL)
 
 link_directories(${CMAKE_CURRENT_BINARY_DIR})