--- a/CMakeLists.txt	Sat Sep 15 15:57:56 2018 +0300
+++ b/CMakeLists.txt	Fri Dec 21 21:43:06 2018 +0200
@@ -26,7 +26,7 @@
 find_package (OpenGL REQUIRED)
 
 add_custom_target (revision_check ALL
-	COMMAND python "${CMAKE_SOURCE_DIR}/tools/updaterevision.py" hginfo.h
+	COMMAND python3 "${CMAKE_SOURCE_DIR}/tools/updaterevision.py" --cwd "$(CMAKE_SOURCE_DIR)" hginfo.h
 	WORKING_DIRECTORY ${CMAKE_BINARY_DIR})
 
 include_directories (${QT_INCLUDES} ${CMAKE_CURRENT_BINARY_DIR})