cmake-gui: Install only necessary plugins for Qt 6

Source/QtDialog/CMakeLists.txt

@@ -105,32 +105,15 @@ if(CMake_INSTALL_DEPENDENCIES AND (APPLE OR WIN32))
         "${${_qt_plugins_var}};\$ENV{DESTDIR}\${CMAKE_INSTALL_PREFIX}/${_qt_plugin_dest}/${_qt_plugin_file}")
     endif()
   endmacro()
-  macro(install_qt_plugins _comps _plugins_var)
-    foreach(_qt_comp IN LISTS ${_comps})
-      if(CMake_QT_MAJOR_VERSION VERSION_LESS 6)
-        set(_qt_module_plugins ${Qt${CMake_QT_MAJOR_VERSION}${_qt_comp}_PLUGINS})
-      else()
-        get_target_property(_qt_module_plugins Qt${CMake_QT_MAJOR_VERSION}::${_qt_comp} QT_PLUGINS)
-      endif()
-      foreach(_qt_plugin IN LISTS _qt_module_plugins)
-        if(CMake_QT_MAJOR_VERSION VERSION_GREATER_EQUAL 6)
-          # Qt6 provides the plugins as individual packages that need to be found.
-          find_package(Qt${CMake_QT_MAJOR_VERSION}${_qt_plugin} QUIET
-            PATHS ${Qt${CMake_QT_MAJOR_VERSION}${_qt_comp}_DIR})
-        endif()
-        install_qt_plugin("${_qt_plugin}" "${_plugins_var}")
-      endforeach()
-    endforeach()
-  endmacro()
   if(APPLE)
-    if(CMake_QT_MAJOR_VERSION VERSION_EQUAL 5)
-      install_qt_plugin("Qt5::QCocoaIntegrationPlugin" QT_PLUGINS)
-      if(TARGET Qt5::QMacStylePlugin)
-        install_qt_plugin("Qt5::QMacStylePlugin" QT_PLUGINS)
-      endif()
-    else()
-      # FIXME: Minimize plugins for Qt6.
-      install_qt_plugins(QT_COMPONENTS QT_PLUGINS)
+    if(CMake_QT_MAJOR_VERSION VERSION_GREATER_EQUAL 6)
+      # Qt6 provides the plugins as individual packages that need to be found.
+      find_package(Qt${CMake_QT_MAJOR_VERSION}QCocoaIntegrationPlugin QUIET PATHS ${Qt${CMake_QT_MAJOR_VERSION}Gui_DIR})
+      find_package(Qt${CMake_QT_MAJOR_VERSION}QMacStylePlugin QUIET PATHS ${Qt${CMake_QT_MAJOR_VERSION}Widgets_DIR})
+    endif()
+    install_qt_plugin("Qt${CMake_QT_MAJOR_VERSION}::QCocoaIntegrationPlugin" QT_PLUGINS)
+    if(TARGET Qt${CMake_QT_MAJOR_VERSION}::QMacStylePlugin)
+      install_qt_plugin("Qt${CMake_QT_MAJOR_VERSION}::QMacStylePlugin" QT_PLUGINS)
     endif()
     file(WRITE "${CMAKE_CURRENT_BINARY_DIR}/qt.conf"
       "[Paths]\nPlugins = ${_qt_plugin_dir}\n")
@@ -138,12 +121,11 @@ if(CMake_INSTALL_DEPENDENCIES AND (APPLE OR WIN32))
       DESTINATION "${CMake_INSTALL_APP_DIR_SLASH}Resources"
       ${COMPONENT})
   elseif(WIN32 AND NOT CMake_QT_STATIC_QWindowsIntegrationPlugin_LIBRARIES)
-    if(CMake_QT_MAJOR_VERSION VERSION_EQUAL 5)
-      install_qt_plugin("Qt5::QWindowsIntegrationPlugin" QT_PLUGINS)
-    else()
-      # FIXME: Minimize plugins for Qt6.
-      install_qt_plugins(QT_COMPONENTS QT_PLUGINS)
+    if(CMake_QT_MAJOR_VERSION VERSION_GREATER_EQUAL 6)
+      # Qt6 provides the plugins as individual packages that need to be found.
+      find_package(Qt${CMake_QT_MAJOR_VERSION}QWindowsIntegrationPlugin QUIET PATHS ${Qt${CMake_QT_MAJOR_VERSION}Gui_DIR})
     endif()
+    install_qt_plugin("Qt${CMake_QT_MAJOR_VERSION}::QWindowsIntegrationPlugin" QT_PLUGINS)
     file(WRITE "${CMAKE_CURRENT_BINARY_DIR}/qt.conf"
       "[Paths]\nPlugins = ../${_qt_plugin_dir}\n")
     install(FILES "${CMAKE_CURRENT_BINARY_DIR}/qt.conf"