cmake: use CMAKE_BUILD_TYPE instead of CONFIGURATION as BUILD_DIRECTIVE

(cherry picked from commit 06391e5e9dff58a265d42a8a8093d0a57b8e2775)

cmake/compiler/clang/settings.cmake

@@ -1,5 +1,5 @@
 # Set build-directive (used in core to tell which buildtype we used)
-add_definitions(-D_BUILD_DIRECTIVE='"$(CONFIGURATION)"')
+add_definitions(-D_BUILD_DIRECTIVE='"${CMAKE_BUILD_TYPE}"')
 
 if(WITH_WARNINGS)
   set(WARNING_FLAGS "-W -Wall -Wextra -Winit-self -Wfatal-errors -Wno-mismatched-tags")