Add ENOTSUP constant for riscv32/musl

Author: kraj

src/unix/linux_like/linux/musl/b32/riscv32/mod.rs

@@ -271,6 +271,7 @@ pub const ENOPROTOOPT: ::c_int = 92;
 pub const EPROTONOSUPPORT: ::c_int = 93;
 pub const ESOCKTNOSUPPORT: ::c_int = 94;
 pub const EOPNOTSUPP: ::c_int = 95;
+pub const ENOTSUP: ::c_int = EOPNOTSUPP;
 pub const EPFNOSUPPORT: ::c_int = 96;
 pub const EAFNOSUPPORT: ::c_int = 97;
 pub const EADDRINUSE: ::c_int = 98;