Hide content of pthread_cond_t in pthread_cond_internal_t.

Bug: 19249079
Change-Id: I6f55af30bcd6211ce71630c6cacbef0e1663dcee
diff --git a/libc/include/pthread.h b/libc/include/pthread.h
index c701e30..b0389e8 100644
--- a/libc/include/pthread.h
+++ b/libc/include/pthread.h
@@ -73,13 +73,14 @@
 };
 
 typedef struct {
-  unsigned int value;
-#ifdef __LP64__
-  char __reserved[44];
+#if defined(__LP64__)
+  char __private[48];
+#else
+  char __private[4];
 #endif
 } pthread_cond_t;
 
-#define PTHREAD_COND_INITIALIZER  {0 __RESERVED_INITIALIZER}
+#define PTHREAD_COND_INITIALIZER  { { 0 } }
 
 typedef long pthread_mutexattr_t;
 typedef long pthread_condattr_t;