Tell the compiler to be more pedantic for debug builds.

CMakeLists.txt

@@ -16,7 +16,8 @@ set(CMAKE_CXX_STANDARD 14)
 set(CMAKE_CXX_STANDARD_REQUIRED ON)
 set(CMAKE_CXX_EXTENSIONS OFF)
 
-set(CMAKE_CXX_FLAGS_DEBUG "${CMAKE_CXX_FLAGS_DEBUG} -Wall -g -Og")
+set(CMAKE_CXX_FLAGS_DEBUG
+    "${CMAKE_CXX_FLAGS_DEBUG} -Wall -pedantic -Wextra -g -Og")
 
 # Do not complain about compatibility-wrapper
 if(NOT CMAKE_BUILD_TYPE STREQUAL "Debug")