Fix build: align pthread_cond_t to sizeof(long)

Change-Id: Ieaee6d09089b161ec516ba22cafaee1ecb4342da
diff --git a/libc/include/pthread.h b/libc/include/pthread.h
index 38282ad..09ea113 100644
--- a/libc/include/pthread.h
+++ b/libc/include/pthread.h
@@ -78,7 +78,7 @@
 #else
   char __private[4];
 #endif
-} pthread_cond_t __attribute__((aligned(8)));
+} pthread_cond_t __attribute__((aligned(sizeof(long))));
 
 #define PTHREAD_COND_INITIALIZER  { { 0 } }