On Tue, 2025-02-18 at 16:32 -0500, Zack Weinberg wrote: > 2) Besides an "is this feature available" probe, I don't know if any > support for C++ 2020 modules is even *necessary*, because I don't > know how they work. If any other changes are necessary, they would > probably need to happen in Automake and Libtool, not in Autoconf.
Definitely build systems need to be made module-aware, at some level, for them to work correctly. It might be helpful to read about what CMake did to enable C++ modules: https://cmake.org/cmake/help/latest/manual/cmake-cxxmodules.7.html You'll note they didn't implement it for makefiles :-/ :-) There was some very experimental work done alongside GNU Make a number of years ago, but back then it wasn't clear how we would move forward with "module descriptions". There were two ideas: one of them a "scanner" which was sort of like the old makedepend or gcc -MM or whatever that generated a description of module dependencies, and the other an LSP-like client-server solution. My position so far, from a GNU Make standpoint, is that it's not been feasible to know how best to proceed, yet. Maybe that is starting to change and the compilers are coalescing around a solution that GNU Make could work with.
