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

fusl/arch/aarch64/bits/msg.h

+struct msqid_ds
+{
+        struct ipc_perm msg_perm;
+        time_t msg_stime;
+        time_t msg_rtime;
+        time_t msg_ctime;
+        unsigned long msg_cbytes;
+        msgqnum_t msg_qnum;
+        msglen_t msg_qbytes;
+        pid_t msg_lspid;
+        pid_t msg_lrpid;
+        unsigned long __pad1;
+        unsigned long __pad2;
+};