revert back to matching kevent64_s definition from OS X man page for kevent

Author: dgrove-oss

os/linux_base.h

@@ -71,18 +71,16 @@ typedef void (*dispatch_mach_msg_destructor_t)(void*);
 
 /*
  * Stub out defines for other missing types
- * introduced kevent64_s exactly as kevent. this code does not seem to use the 
- * flags field that OS-X defines in its kevent64_s structure
  */
 
 struct kevent64_s {
-    uintptr_t       ident;          /* identifier for this event */
+    uint64_t        ident;          /* identifier for this event */
     int16_t         filter;         /* filter for event */
     uint16_t        flags;          /* general flags */
     uint32_t        fflags;         /* filter-specific flags */
-    intptr_t        data;           /* filter-specific data */
-    void            *udata;         /* opaque user data identifier */
-    uintptr_t       ext[2];       
+    int64_t         data;           /* filter-specific data */
+    uint64_t        udata;          /* opaque user data identifier */
+    uint64_t        ext[2];         /* filter-specific extensions */
 };
 
 typedef uint32_t voucher_activity_mode_t;