skip build graphic3d if QtDataVisualization absent

libs/graphic3d/CMakeLists.txt

@@ -1,4 +1,16 @@
 if (HAS_GL)
-	qad_library(graphic3d "Gui;Widgets;DataVisualization" "")
+	set(HAS_QtDataVisualization ON)
+	foreach(_v ${_QT_VERSIONS_})
+		if (Qt${_v}Core_FOUND)
+			find_package(Qt${_v} COMPONENTS DataVisualization QUIET)
+			if (NOT Qt${_v}DataVisualization_FOUND)
+				message(STATUS "Qt${_v} DataVisualization NOT FOUND -> skip build QAD::graphic3d")
+				set(HAS_QtDataVisualization OFF)
+			endif()
+		endif()
+	endforeach()
+	if (HAS_QtDataVisualization)
+		qad_library(graphic3d "Gui;Widgets;DataVisualization" "")
+	endif()
 endif()