Add missing includes.

Change-Id: Ibd96e0f337f22b4cf4db09e42b06c6eb645472d9
Exempt-From-Owner-Approval: trivial cleanup
Test: mma
Bug: None
diff --git a/vulkan/nulldrv/null_driver.cpp b/vulkan/nulldrv/null_driver.cpp
index a3da651..c701d48 100644
--- a/vulkan/nulldrv/null_driver.cpp
+++ b/vulkan/nulldrv/null_driver.cpp
@@ -16,6 +16,7 @@
 
 #include <hardware/hwvulkan.h>
 
+#include <errno.h>
 #include <inttypes.h>
 #include <stdlib.h>
 #include <string.h>