Emscripten version numbers are unrelated to Clang version numbers,
so it is necessary to change the version checks for `c_std=c17` & co.
Without that, no project that defaults to C17 or newer will build with
Emscripten.
See https://github.com/pyodide/pyodide/discussions/4762 for more
context. Also note that this bug caused defaulting to C17 in
scikit-learn to be reverted (scikit-learn#29015), and it may be a
problem for SciPy 1.14.0 too since that release will upgrade from C99
to C17.
Co-authored-by: Loic Esteve <loic.esteve@ymail.com>
Ralf Gommers
77db04ffa6