Fix qtbase cmake for gui plugins

It should fix "Broken cmake file with Qt5.10 full" #40706.

I leave to @ttuegel rearranging the patches.

pkgs/development/libraries/qt-5/5.11/default.nix

@@ -53,6 +53,7 @@ let
       ./qtbase.patch
       ./qtbase-darwin.patch
       ./qtbase-revert-no-macos10.10.patch
+      ./qtbase-fixguicmake.patch
     ] ++ optionals stdenv.isDarwin [
       ./qtbase-darwin-nseventtype.patch
     ];

pkgs/development/libraries/qt-5/5.11/qtbase-fixguicmake.patch

@@ -0,0 +1,30 @@
+diff --git a/mkspecs/features/data/cmake/Qt5BasicConfig.cmake.in b/mkspecs/features/data/cmake/Qt5BasicConfig.cmake.in
+index 0bbc871..3673634 100644
+--- a/mkspecs/features/data/cmake/Qt5BasicConfig.cmake.in
++++ b/mkspecs/features/data/cmake/Qt5BasicConfig.cmake.in
+@@ -286,7 +286,7 @@ if (NOT TARGET Qt5::$${CMAKE_MODULE_NAME})
+     macro(_populate_$${CMAKE_MODULE_NAME}_plugin_properties Plugin Configuration PLUGIN_LOCATION)
+         set_property(TARGET Qt5::${Plugin} APPEND PROPERTY IMPORTED_CONFIGURATIONS ${Configuration})
+
+-        set(imported_location \"$${CMAKE_PLUGIN_DIR}${PLUGIN_LOCATION}\")
++        set(imported_location \"${PLUGIN_LOCATION}\")
+         _qt5_$${CMAKE_MODULE_NAME}_check_file_exists(${imported_location})
+         set_target_properties(Qt5::${Plugin} PROPERTIES
+             \"IMPORTED_LOCATION_${Configuration}\" ${imported_location}
+diff --git a/mkspecs/features/data/cmake/Qt5PluginTarget.cmake.in b/mkspecs/features/data/cmake/Qt5PluginTarget.cmake.in
+index 5baf0fd..3583745 100644
+--- a/mkspecs/features/data/cmake/Qt5PluginTarget.cmake.in
++++ b/mkspecs/features/data/cmake/Qt5PluginTarget.cmake.in
+@@ -2,10 +2,10 @@
+ add_library(Qt5::$$CMAKE_PLUGIN_NAME MODULE IMPORTED)
+
+ !!IF !isEmpty(CMAKE_RELEASE_TYPE)
+-_populate_$${CMAKE_MODULE_NAME}_plugin_properties($$CMAKE_PLUGIN_NAME RELEASE \"$${CMAKE_PLUGIN_LOCATION_RELEASE}\")
++_populate_$${CMAKE_MODULE_NAME}_plugin_properties($$CMAKE_PLUGIN_NAME RELEASE \"$${CMAKE_PLUGIN_DIR}$${CMAKE_PLUGIN_LOCATION_RELEASE}\")
+ !!ENDIF
+ !!IF !isEmpty(CMAKE_DEBUG_TYPE)
+-_populate_$${CMAKE_MODULE_NAME}_plugin_properties($$CMAKE_PLUGIN_NAME DEBUG \"$${CMAKE_PLUGIN_LOCATION_DEBUG}\")
++_populate_$${CMAKE_MODULE_NAME}_plugin_properties($$CMAKE_PLUGIN_NAME DEBUG \"$${CMAKE_PLUGIN_DIR}$${CMAKE_PLUGIN_LOCATION_DEBUG}\")
+ !!ENDIF
+
+ list(APPEND Qt5$${CMAKE_MODULE_NAME}_PLUGINS Qt5::$$CMAKE_PLUGIN_NAME)