CMAKE_USER_MAKE_RULES_OVERRIDE

CMakeLists.txt

cmake_minimum_required(...)

set(CMAKE_USER_MAKE_RULES_OVERRIDE "cmake/init_flags.cmake")

project(...)

init_flags.cmake

# Debug level 3 includes extra information, such as all the macro definitions present in the program
foreach(lang IN ITEMS C CXX)
  foreach(config IN ITEMS DEBUG RELWITHDEBINFO)
    if(DEFINED CMAKE_${lang}_FLAGS_${config}_INIT AND NOT CMAKE_${lang}_FLAGS_${config}_INIT MATCHES "-g3")
      message(STATUS "Changing CMAKE_${lang}_FLAGS_${config}_INIT")
      message(STATUS "  From: ${CMAKE_${lang}_FLAGS_${config}_INIT}")
      string(REPLACE "-g" "-g3" CMAKE_${lang}_FLAGS_${config}_INIT "${CMAKE_${lang}_FLAGS_${config}_INIT}")
      message(STATUS "  To:   ${CMAKE_${lang}_FLAGS_${config}_INIT}")
      message(STATUS "Changing CMAKE_${lang}_FLAGS_${config}_INIT - done")
    endif()
  endforeach()
endforeach()