diff --git a/libc/include/pthread.h b/libc/include/pthread.h
index 3f59b91..f93f9e9 100644
--- a/libc/include/pthread.h
+++ b/libc/include/pthread.h
@@ -35,26 +35,17 @@
 #include <limits.h>
 #include <sys/types.h>
 
-#ifdef __LP64__
-  #define __RESERVED_INITIALIZER , {0}
-#else
-  #define __RESERVED_INITIALIZER
-#endif
-
 typedef struct {
   int volatile value;
-#ifdef __LP64__
-  char __reserved[36];
-#endif
 } pthread_mutex_t;
 
 #define  __PTHREAD_MUTEX_INIT_VALUE            0
 #define  __PTHREAD_RECURSIVE_MUTEX_INIT_VALUE  0x4000
 #define  __PTHREAD_ERRORCHECK_MUTEX_INIT_VALUE 0x8000
 
-#define  PTHREAD_MUTEX_INITIALIZER             {__PTHREAD_MUTEX_INIT_VALUE __RESERVED_INITIALIZER}
-#define  PTHREAD_RECURSIVE_MUTEX_INITIALIZER   {__PTHREAD_RECURSIVE_MUTEX_INIT_VALUE __RESERVED_INITIALIZER}
-#define  PTHREAD_ERRORCHECK_MUTEX_INITIALIZER  {__PTHREAD_ERRORCHECK_MUTEX_INIT_VALUE __RESERVED_INITIALIZER}
+#define  PTHREAD_MUTEX_INITIALIZER             {__PTHREAD_MUTEX_INIT_VALUE}
+#define  PTHREAD_RECURSIVE_MUTEX_INITIALIZER   {__PTHREAD_RECURSIVE_MUTEX_INIT_VALUE}
+#define  PTHREAD_ERRORCHECK_MUTEX_INITIALIZER  {__PTHREAD_ERRORCHECK_MUTEX_INIT_VALUE}
 
 enum {
     PTHREAD_MUTEX_NORMAL = 0,
@@ -69,12 +60,9 @@
 
 typedef struct {
   int volatile value;
-#ifdef __LP64__
-  char __reserved[44];
-#endif
 } pthread_cond_t;
 
-#define PTHREAD_COND_INITIALIZER  {0 __RESERVED_INITIALIZER}
+#define PTHREAD_COND_INITIALIZER  {0}
 
 typedef struct {
   uint32_t flags;
@@ -83,9 +71,6 @@
   size_t guard_size;
   int32_t sched_policy;
   int32_t sched_priority;
-#ifdef __LP64__
-  char __reserved[16];
-#endif
 } pthread_attr_t;
 
 typedef long pthread_mutexattr_t;
@@ -94,13 +79,13 @@
 typedef int pthread_rwlockattr_t;
 
 typedef struct {
-  pthread_mutex_t lock;
-  pthread_cond_t cond;
-  int numLocks;
-  int writerThreadId;
-  int pendingReaders;
-  int pendingWriters;
-  void* __reserved[4];
+  pthread_mutex_t  lock;
+  pthread_cond_t   cond;
+  int              numLocks;
+  int              writerThreadId;
+  int              pendingReaders;
+  int              pendingWriters;
+  void*            reserved[4];  /* for future extensibility */
 } pthread_rwlock_t;
 
 #define PTHREAD_RWLOCK_INITIALIZER  { PTHREAD_MUTEX_INITIALIZER, PTHREAD_COND_INITIALIZER, 0, 0, 0, 0, { NULL, NULL, NULL, NULL } }
@@ -110,7 +95,7 @@
 
 typedef volatile int pthread_once_t;
 
-#define PTHREAD_ONCE_INIT 0
+#define PTHREAD_ONCE_INIT    0
 
 #define PTHREAD_STACK_MIN (2 * PAGE_SIZE)