MSYS: fix broken Qt6 build using MinGW & clang

src/Gui/CMakeLists.txt

@@ -91,6 +91,7 @@ include_directories(
     ${QtSvgWidgets_INCLUDE_DIRS}
     ${QtNetwork_INCLUDE_DIRS}
     ${QtUiTools_INCLUDE_DIRS}
+    ${QtXml_INCLUDE_DIRS}
 )
 list(APPEND FreeCADGui_LIBS
     ${QtCore_LIBRARIES}

src/Gui/DlgPreferencesImp.cpp

@@ -53,8 +53,6 @@
 #include "Tools.h"
 #include "WidgetFactory.h"
 
-#include <QDesktopWidget>
-
 using namespace Gui::Dialog;
 
 QWidget* PreferencesPageItem::getWidget() const

src/Main/CMakeLists.txt

@@ -1,5 +1,3 @@
-#add_defintions(-D_FC_GUI_ENABLED_)
-#add_defintions(-DFREECADMAINPY)
 
 configure_file(freecad.rc.cmake ${CMAKE_CURRENT_BINARY_DIR}/freecad.rc)
 configure_file(freecadCmd.rc.cmake ${CMAKE_CURRENT_BINARY_DIR}/freecadCmd.rc)
@@ -10,6 +8,7 @@ if(BUILD_GUI)
         ${Boost_INCLUDE_DIRS}
         ${COIN3D_INCLUDE_DIRS}
         ${ZLIB_INCLUDE_DIR}
+        ${QtWidgets_INCLUDE_DIRS}
         ${QT_INCLUDE_DIR}
         ${PYTHON_INCLUDE_DIRS}
         ${XercesC_INCLUDE_DIRS}

tests/src/Mod/Material/App/CMakeLists.txt

@@ -9,3 +9,7 @@ target_sources(
     ${CMAKE_CURRENT_SOURCE_DIR}/TestModel.cpp
     ${CMAKE_CURRENT_SOURCE_DIR}/TestModelProperties.cpp
 )
+
+target_include_directories(Material_tests_run PUBLIC
+    ${QtCore_INCLUDE_DIRS}
+)