Fix:build:do not request CXX if explicitly disabled

Signed-off-by: mvglasow <michael -at- vonglasow.com>

CMakeLists.txt

@@ -3,7 +3,11 @@ cmake_minimum_required(VERSION 3.2)
 set(MACOSX_BUNDLE_GUI_IDENTIFIER "org.navitproject.navit")
 set(MACOSX_BUNDLE_BUNDLE_NAME "Navit")
 message(STATUS "Building with CMake V${CMAKE_VERSION}")
-project(navit C CXX)
+if (DISABLE_CXX)
+	project(navit C)
+else(DISABLE_CXX)
+	project(navit C CXX)
+endif(DISABLE_CXX)
 
 # Workaround for CMake issue 8345 / 9220, see http://trac.navit-project.org/ticket/1041
 if(DEFINED CMAKE_CXX_COMPILER AND CMAKE_CXX_COMPILER MATCHES "^$")