Add a "fork" of musl as //fusl.

fusl/arch/x32/bits/socket.h

+struct msghdr
+{
+        void *msg_name;
+        socklen_t msg_namelen;
+        struct iovec *msg_iov;
+        int msg_iovlen, __pad1;
+        void *msg_control;
+        socklen_t msg_controllen, __pad2;
+        int msg_flags;
+};
+
+struct cmsghdr
+{
+        socklen_t cmsg_len;
+        int __pad1;
+        int cmsg_level;
+        int cmsg_type;
+};