C, still?

There are proposals for modules in the standards committee. The problem with it that I see is that it will require massive overhauls to all of the build tools for proper support. Unless you can determine the module output just from the filename or a basic scan of a file's contents, you need to compile it to see what modules a file will create or consume, so you need a pass before everything else that determines this before you start your real compilation. For example, ninja currently has no support for this (see Brad King's PRs for Fortan support; it's the same logic necessary).