Allowing users to override CFLAGS, CXXFLAGS and friends

Question

Typical makefiles often use the built-in variables CFLAGS, CXXFLAGS, CPPFLAGS and so on¹ to set the flags passed to the C,

Answer 1

I am faced with the same problem. For the time being my solution is to provide "non-standard" flags such as OPTIMS, WARNINGS, MODENV which will be appended to the "standard" CXXFLAGS internally.

If the user defines CXXFLAGS from the command-line it is assumed that he wants to override it, and if that's what he wants, that's what he should get: an override. Ironically this means I'm not using override CXXFLAGS += ... in the Makefile.

I don't want advanced users to pull their hairs out because I insist on appending/prepending my stuff to their flags, so in my opinion the final situation is like this:

• GOOD: require advanced users to pass intricate custom flags
• BAD: require advanced users to patch the Makefile