am bce402a8: Merge "qemu_pipe: fix Mac build error."

* commit 'bce402a8fadf27b07b164b0468e27bb9b6de79e6':
  qemu_pipe: fix Mac build error.
diff --git a/include/hardware/qemu_pipe.h b/include/hardware/qemu_pipe.h
index 930228e..000c99e 100644
--- a/include/hardware/qemu_pipe.h
+++ b/include/hardware/qemu_pipe.h
@@ -23,6 +23,7 @@
 #include <pthread.h>  /* for pthread_once() */
 #include <stdlib.h>
 #include <stdio.h>
+#include <errno.h>
 
 #ifndef D
 #  define  D(...)   do{}while(0)