diff -urp src.old/winsup/cygwin/include/cygwin/types.h src/winsup/cygwin/include/cygwin/types.h
--- src.old/winsup/cygwin/include/cygwin/types.h	Tue Jun 11 04:52:18 2002
+++ src/winsup/cygwin/include/cygwin/types.h	Fri Jul  5 10:02:31 2002
@@ -61,14 +61,21 @@ typedef __gid16_t gid_t;
 
 #if !defined(__INSIDE_CYGWIN__) || !defined(__cplusplus)
 
-typedef void *pthread_t;
-typedef void *pthread_mutex_t;
+typedef struct {char __dummy;} __pthread_t;
+typedef __pthread_t *pthread_t;
+typedef struct {char __dummy;} __pthread_mutex_t;
+typedef __pthread_mutex_t *pthread_mutex_t;
 
-typedef void *pthread_key_t;
-typedef void *pthread_attr_t;
-typedef void *pthread_mutexattr_t;
-typedef void *pthread_condattr_t;
-typedef void *pthread_cond_t;
+typedef struct {char __dummy;} __pthread_key_t;
+typedef __pthread_key_t *pthread_key_t;
+typedef struct {char __dummy;} __pthread_attr_t;
+typedef __pthread_attr_t *pthread_attr_t;
+typedef struct {char __dummy;} __pthread_mutexattr_t;
+typedef __pthread_mutexattr_t *pthread_mutexattr_t;
+typedef struct {char __dummy;} __pthread_condattr_t;
+typedef __pthread_condattr_t *pthread_condattr_t;
+typedef struct {char __dummy;} __pthread_cond_t;
+typedef __pthread_cond_t *pthread_cond_t;
 
   /* These variables are not user alterable. This means you!. */
 typedef struct
@@ -77,8 +84,10 @@ typedef struct
   int state;
 }
 pthread_once_t;
-typedef void *pthread_rwlock_t;
-typedef void *pthread_rwlockattr_t;
+typedef struct {char __dummy;} __pthread_rwlock_t;
+typedef __pthread_rwlock_t *pthread_rwlock_t;
+typedef struct {char __dummy;} __pthread_rwlockattr_t;
+typedef __pthread_rwlockattr_t *pthread_rwlockattr_t;
 
 #else
 
diff -urp src.old/winsup/cygwin/include/semaphore.h src/winsup/cygwin/include/semaphore.h
--- src.old/winsup/cygwin/include/semaphore.h	Wed Mar 21 16:06:22 2001
+++ src/winsup/cygwin/include/semaphore.h	Fri Jul  5 10:02:32 2002
@@ -21,7 +21,8 @@ extern "C"
 #endif
 
 #ifndef __INSIDE_CYGWIN__
-  typedef void *sem_t;
+  typedef struct {char __dummy;} __sem_t;
+  typedef __sem_t *sem_t;
 #endif
 
 #define SEM_FAILED 0