diff --git a/sys/kern/syscalls.master b/sys/kern/syscalls.master
index 96541023ec2..92cc727f22c 100644
--- a/sys/kern/syscalls.master
+++ b/sys/kern/syscalls.master
@@ -114,9 +114,12 @@
 #include <sys/sysproto.h>
 %%ABI_HEADERS%%
 
-0	AUE_NULL	STD {
-		int nosys(void);
-	} syscall nosys_args int
+0	AUE_NULL	SYSMUX {
+		int syscall(
+		    int number,
+		    ...
+		);
+	}
 1	AUE_EXIT	STD|CAPENABLED {
 		void exit(
 		    int rval
@@ -1194,9 +1197,12 @@
 		    off_t pos
 		);
 	}
-198	AUE_NULL	NOPROTO {
-		int nosys(void);
-	} __syscall __syscall_args int
+198	AUE_NULL	SYSMUX {
+		int __syscall(
+		    int64_t number,
+		    ...
+		);
+	}
 199	AUE_LSEEK	COMPAT6|CAPENABLED {
 		off_t lseek(
 		    int fd,
diff --git a/sys/sys/sysent.h b/sys/sys/sysent.h
index fc678d49750..e0b06792703 100644
--- a/sys/sys/sysent.h
+++ b/sys/sys/sysent.h
@@ -192,6 +192,12 @@ extern struct sysentvec aout_sysvec;
 extern struct sysent sysent[];
 extern const char *syscallnames[];
 
+struct nosys_args {
+	register_t dummy;
+};
+
+int	nosys(struct thread *, struct nosys_args *);
+
 #define	NO_SYSCALL (-1)
 
 struct module;