Add missing includes.

Test: mma
Bug: None
Change-Id: I0221b213e08d07cc5ac0b704a86e98ae8c0f456f
diff --git a/libc/upstream-openbsd/android/include/arc4random.h b/libc/upstream-openbsd/android/include/arc4random.h
index 4c4be0e..afa8d14 100644
--- a/libc/upstream-openbsd/android/include/arc4random.h
+++ b/libc/upstream-openbsd/android/include/arc4random.h
@@ -22,10 +22,10 @@
  * Stub functions for portability.
  */
 
-#include <sys/mman.h>
-
+#include <errno.h>
 #include <pthread.h>
 #include <signal.h>
+#include <sys/mman.h>
 
 #include <async_safe/log.h>