[wahern]

People are too quick to [ab]use GNU Make features. IME, learning how to make do with portable make constructs can help discipline oneself to avoid excessive complexity, especially when it comes to macro definitions where GNU Make's Lispy looping and eval constructs are heavily overused and quickly lead to obtuse, impenetrable code. POSIX pattern substitutions are quite powerful and often produce easier to read code than the GNU equivalent. I'm not sure if computed variable names/nested variable references are well-defined in POSIX (e.g. "$($(FOO))"), but they are widely supported nonetheless, and often more readable than $(eval ...). (They can also be used for portable conditional constructs; I wouldn't argue they're more readable, though I often find them so.)

Some GNU Make constructs, like pattern rules, are indispensable in all but the simplest projects, but can also be overused.

For some reason there's a strong urge to programmatically generate build rules. But like with SQL queries, going beyond the parameterization already built into the language can be counter productive. A good Makefile, like a good SQL query, should be easy to read on its face. Yes, it often means greater verbosity and even repetition, but that can be a benefit to be embraced (at least embraced more than is instinctively common).

EDIT: Computed variable references are well-defined as of POSIX-2024, including (AFAICT) on the left-hand side of a definition. In the discussion it was shown the semantics were already supported by all extant implementations.

[f1shy]

Absolutely. But the target has nothing to do with “portability” but a more fundamental and important principle(s) of readability and maintainability.

[wahern]

It's a matter of praxis. Targeting portable constructs is (IMO) a useful methodology for achieving the abstract goal. It doesn't have to be strict, but it provides a quantifiable, objective metric (i.e. amount of non-portable constructs employed) to help achieve an otherwise subjective goal.

Otherwise you face an ocean of choices that can be overwhelming, especially if you're not very experienced in the problem space. It's like the common refrain with C++: most developers settle on a subset of C++ to minimize code complexity; but which subset? (They can vary widely, across projects and time.) In the case of Make, you can just pick the POSIX and/or de facto portable subset as your target, avoiding alot of choice paralysis/anxiety (though you still face it when deciding when to break out of that box to leverage GNU extensions).