Makefiles: use of CPPFLAGS

[GitMensch]

Currently CFLAGS is used for everything - shouldn't defines and include options all go to CPPFLAGS instead?

A side not, just to share, as I forgot about this:
make CFLAGS=something overrides CFLAGS in the makefile completely, while CFLAGS=something make actually extend those if CFLAGS += is used in the makefile (what we already do), so this specific option should not be passed to make but come from the environment.

[Bill-Gray]

Despite having written code in C and C++ for nearly 40 years, I was unclear on this subject. The difference between CFLAGS and CPPFLAGS turns out to be quite simple (basically, you're right).

It's particularly odd that I hadn't run into the difference before, since some of my projects involve a mix of C and C++. In such cases, the C-specific stuff (say, -std=c90) should go with CFLAGS. The C++-specific stuff (say, -std=c++03) should go into CXXFLAGS. (Not an issue for C++-less PDCursesMod, I realize.) And the stuff that would go through the preprocessor (include directories and defines, as you mention) should go to CPPFLAGS.

Now that I know about the distinction, it makes considerable sense to me.

As to adding flags : are there currently use cases for this? That is to say, situations where we'd like the ability to tell make "please add the following to CFLAGS"? We could have something like make ADDED_CFLAGS=something, but I can't think of a case where we actually do anything like that. (Except indirectly; `UTF8=Y' causes compiler flags to be added, for example.)