Add option to skip headers check

In some configuration, such as our docker build, there's no need to
perform headers check, as it is handled by a different job already.

CMakeLists.txt

@@ -113,9 +113,10 @@ option(DISABLE_TTF "Disable support for TTF provided by freetype2.")
 option(ENABLE_SCRIPTING "Enable script / plugin support." ON)
 option(ENABLE_ASAN "Enable the AddressSanitizer.")
 option(ENABLE_UBSAN "Enable the UndefinedBehaviourSanitizer.")
-
+option(ENABLE_HEADERS_CHECK "Check if include directives in header files are correct. Only works with clang" ON)
 option(DISABLE_GUI "Don't build GUI. (Headless only.)")
 
+
 if (FORCE32)
     set(TARGET_M "-m32")
     set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${TARGET_M}")