Enables build for *-linux-musl (#1627)

Also contributes to being able to build for *-w64-mingw32.

Cf. https://github.com/JuliaPackaging/Yggdrasil/pull/9761

mlx/utils.cpp

@@ -152,7 +152,7 @@ std::ostream& operator<<(std::ostream& os, int8_t x) {
 }
 
 std::ostream& operator<<(std::ostream& os, uint8_t x) {
-  os << static_cast<uint>(x);
+  os << static_cast<unsigned int>(x);
   return os;
 }