Jacek Caban (@jacek) commented about libs/musl/src/math/rint.c:
double __cdecl rint(double x) { -#if defined(__GNUC__) || defined(__clang__) +#if defined(__GNUC__)
`__GNUC__` is defined in Clang mingw mode, something like `&& !defined(__clang__)` would catch it.