diff --git a/lib/libc/gen/_spinlock_stub.c b/lib/libc/gen/_spinlock_stub.c
index a130c8e46e84..47bbfeb3fbdc 100644
--- a/lib/libc/gen/_spinlock_stub.c
+++ b/lib/libc/gen/_spinlock_stub.c
@@ -34,6 +34,11 @@ __FBSDID("$FreeBSD$");
 
 #include "spinlock.h"
 
+long _atomic_lock_stub(volatile long *);
+void _spinlock_stub(spinlock_t *);
+void _spinunlock_stub(spinlock_t *);
+void _spinlock_debug_stub(spinlock_t *, char *, int);
+
 /*
  * Declare weak definitions in case the application is not linked
  * with libpthread.
@@ -43,12 +48,11 @@ __weak_reference(_spinlock_stub, _spinlock);
 __weak_reference(_spinunlock_stub, _spinunlock);
 __weak_reference(_spinlock_debug_stub, _spinlock_debug);
 
-
 /*
  * This function is a stub for the _atomic_lock function in libpthread.
  */
 long
-_atomic_lock_stub(volatile long *lck)
+_atomic_lock_stub(volatile long *lck __unused)
 {
 	return (0L);
 }
@@ -58,7 +62,7 @@ _atomic_lock_stub(volatile long *lck)
  * This function is a stub for the spinlock function in libpthread.
  */
 void
-_spinlock_stub(spinlock_t *lck)
+_spinlock_stub(spinlock_t *lck __unused)
 {
 }
 
@@ -66,7 +70,7 @@ _spinlock_stub(spinlock_t *lck)
  * This function is a stub for the spinunlock function in libpthread.
  */
 void
-_spinunlock_stub(spinlock_t *lck)
+_spinunlock_stub(spinlock_t *lck __unused)
 {
 }
 
@@ -74,6 +78,6 @@ _spinunlock_stub(spinlock_t *lck)
  * This function is a stub for the debug spinlock function in libpthread.
  */
 void
-_spinlock_debug_stub(spinlock_t *lck, char *fname, int lineno)
+_spinlock_debug_stub(spinlock_t *lck __unused, char *fname __unused, int lineno __unused)
 {
 }