diff --git a/servers/avfs/device.c b/servers/avfs/device.c
index 2f2f33b97..21b42dddc 100644
--- a/servers/avfs/device.c
+++ b/servers/avfs/device.c
@@ -597,9 +597,9 @@ PUBLIC int tty_opcl(
  *===========================================================================*/
 PUBLIC int ctty_opcl(
   int op,			/* operation, DEV_OPEN or DEV_CLOSE */
-  dev_t dev,			/* device to open or close */
-  endpoint_t proc_e,		/* process to open/close for */
-  int flags			/* mode bits and flags */
+  dev_t UNUSED(dev),		/* device to open or close */
+  endpoint_t UNUSED(proc_e),	/* process to open/close for */
+  int UNUSED(flags)		/* mode bits and flags */
 )
 {
 /* This procedure is called from the dmap struct on opening or closing
@@ -747,9 +747,10 @@ message *mess_ptr;		/* pointer to message for task */
 /*===========================================================================*
  *				ctty_io					     *
  *===========================================================================*/
-PUBLIC int ctty_io(task_nr, mess_ptr)
-int task_nr;			/* not used - for compatibility with dmap_t */
-message *mess_ptr;		/* pointer to message for task */
+PUBLIC int ctty_io(
+  endpoint_t UNUSED(task_nr),	/* not used - for compatibility with dmap_t */
+  message *mess_ptr		/* pointer to message for task */
+)
 {
 /* This routine is only called for one device, namely /dev/tty.  Its job
  * is to change the message to use the controlling terminal, instead of the
@@ -800,7 +801,7 @@ PUBLIC int no_dev(
 /*===========================================================================*
  *				no_dev_io				     *
  *===========================================================================*/
-PUBLIC int no_dev_io(int proc, message *m)
+PUBLIC int no_dev_io(endpoint_t UNUSED(proc), message *UNUSED(m))
 {
 /* Called when doing i/o on a nonexistent device. */
   printf("VFS: I/O on unmapped device number\n");
diff --git a/servers/avfs/fscall.c b/servers/avfs/fscall.c
index 6098af822..257afb32e 100644
--- a/servers/avfs/fscall.c
+++ b/servers/avfs/fscall.c
@@ -32,10 +32,6 @@ PRIVATE struct {
 
 PRIVATE int depth = 0;			/* current globals stack level */
 
-#if ENABLE_SYSCALL_STATS
-EXTERN unsigned long calls_stats[NCALLS];
-#endif
-
 FORWARD _PROTOTYPE( int push_globals, (void)				);
 FORWARD _PROTOTYPE( void pop_globals, (void)				);
 FORWARD _PROTOTYPE( void set_globals, (message *m)			);
diff --git a/servers/avfs/main.c b/servers/avfs/main.c
index 6426202c0..eccfc82a5 100644
--- a/servers/avfs/main.c
+++ b/servers/avfs/main.c
@@ -475,7 +475,7 @@ PRIVATE void sef_local_startup()
 /*===========================================================================*
  *				sef_cb_init_fresh			     *
  *===========================================================================*/
-PRIVATE int sef_cb_init_fresh(int type, sef_init_info_t *info)
+PRIVATE int sef_cb_init_fresh(int UNUSED(type), sef_init_info_t *info)
 {
 /* Initialize the virtual file server. */
   int s, i;
diff --git a/servers/avfs/select.c b/servers/avfs/select.c
index 98c9b9c1c..b59fe6b1f 100644
--- a/servers/avfs/select.c
+++ b/servers/avfs/select.c
@@ -398,7 +398,8 @@ PRIVATE int select_request_async(struct filp *f, int *ops, int block)
 /*===========================================================================*
  *				select_request_file			     *
  *===========================================================================*/
-PRIVATE int select_request_file(struct filp *f, int *ops, int block)
+PRIVATE int select_request_file(struct filp *UNUSED(f), int *UNUSED(ops),
+  int UNUSED(block))
 {
   /* Files are always ready, so output *ops is input *ops */
   return(SEL_OK);
diff --git a/servers/ds/store.c b/servers/ds/store.c
index 3b7e06f1e..401dc15ad 100644
--- a/servers/ds/store.c
+++ b/servers/ds/store.c
@@ -252,7 +252,7 @@ PRIVATE int map_service(const struct rprocpub *rpub)
 /*===========================================================================*
  *		            sef_cb_init_fresh                                *
  *===========================================================================*/
-PUBLIC int sef_cb_init_fresh(int type, sef_init_info_t *info)
+PUBLIC int sef_cb_init_fresh(int UNUSED(type), sef_init_info_t *info)
 {
 /* Initialize the data store server. */
 	int i, r;
diff --git a/servers/pm/utility.c b/servers/pm/utility.c
index 5b78ca2e2..ff4046335 100644
--- a/servers/pm/utility.c
+++ b/servers/pm/utility.c
@@ -106,8 +106,10 @@ PUBLIC int nice_to_priority(int nice, unsigned* new_q)
 
 	*new_q = MAX_USER_Q + (nice-PRIO_MIN) * (MIN_USER_Q-MAX_USER_Q+1) /
 	    (PRIO_MAX-PRIO_MIN+1);
-	if (*new_q < MAX_USER_Q) *new_q = MAX_USER_Q;	/* shouldn't happen */
-	if (*new_q > MIN_USER_Q) *new_q = MIN_USER_Q;	/* shouldn't happen */
+
+	/* Neither of these should ever happen. */
+	if ((signed) *new_q < MAX_USER_Q) *new_q = MAX_USER_Q;
+	if (*new_q > MIN_USER_Q) *new_q = MIN_USER_Q;
 
 	return (OK);
 }
diff --git a/servers/procfs/main.c b/servers/procfs/main.c
index 193aa94bd..d02c8ad03 100644
--- a/servers/procfs/main.c
+++ b/servers/procfs/main.c
@@ -69,7 +69,7 @@ PRIVATE void init_hook(void)
 /*===========================================================================*
  *				main					     *
  *===========================================================================*/
-PUBLIC int main(int argc, char *argv[])
+PUBLIC int main(void)
 {
 	/* ProcFS entry point.
 	 */
diff --git a/servers/procfs/tree.c b/servers/procfs/tree.c
index e71513fea..404fb6fb1 100644
--- a/servers/procfs/tree.c
+++ b/servers/procfs/tree.c
@@ -371,7 +371,7 @@ PRIVATE void pid_read(struct inode *node)
 /*===========================================================================*
  *				pid_link				     *
  *===========================================================================*/
-PRIVATE int pid_link(struct inode *node, char *ptr, int max)
+PRIVATE int pid_link(struct inode *UNUSED(node), char *ptr, int UNUSED(max))
 {
 	/* The contents of a symbolic link in a PID directory are requested.
 	 * This function is a placeholder for future use.
@@ -386,7 +386,8 @@ PRIVATE int pid_link(struct inode *node, char *ptr, int max)
 /*===========================================================================*
  *				lookup_hook				     *
  *===========================================================================*/
-PUBLIC int lookup_hook(struct inode *parent, char *name, cbdata_t cbdata)
+PUBLIC int lookup_hook(struct inode *parent, char *name,
+	cbdata_t UNUSED(cbdata))
 {
 	/* Path name resolution hook, for a specific parent and name pair.
 	 * If needed, update our own view of the system first; after that,
@@ -432,7 +433,7 @@ PUBLIC int lookup_hook(struct inode *parent, char *name, cbdata_t cbdata)
 /*===========================================================================*
  *				getdents_hook				     *
  *===========================================================================*/
-PUBLIC int getdents_hook(struct inode *node, cbdata_t cbdata)
+PUBLIC int getdents_hook(struct inode *node, cbdata_t UNUSED(cbdata))
 {
 	/* Directory entry retrieval hook, for potentially all files in a
 	 * directory. Make sure that all files that are supposed to be
@@ -478,7 +479,7 @@ PUBLIC int read_hook(struct inode *node, off_t off, char **ptr,
  *				rdlink_hook				     *
  *===========================================================================*/
 PUBLIC int rdlink_hook(struct inode *node, char *ptr, size_t max,
-	cbdata_t cbdata)
+	cbdata_t UNUSED(cbdata))
 {
 	/* Symbolic link resolution hook. Not used yet.
 	 */
diff --git a/servers/vfs/fscall.c b/servers/vfs/fscall.c
index dc758f555..214457afb 100644
--- a/servers/vfs/fscall.c
+++ b/servers/vfs/fscall.c
@@ -32,10 +32,6 @@ PRIVATE struct {
 
 PRIVATE int depth = 0;			/* current globals stack level */
 
-#if ENABLE_SYSCALL_STATS
-EXTERN unsigned long calls_stats[NCALLS];
-#endif
-
 FORWARD _PROTOTYPE( int push_globals, (void)				);
 FORWARD _PROTOTYPE( void pop_globals, (void)				);
 FORWARD _PROTOTYPE( void set_globals, (message *m)			);