Include what we use.

Test: mma
Bug: None
Change-Id: I704787703c2fde533bda066e7c49d9f0c6bd2f26
Exempt-From-Owner-Approval: Janitorial
diff --git a/gralloc/gralloc_module.cpp b/gralloc/gralloc_module.cpp
index d0cb080..38ed3da 100644
--- a/gralloc/gralloc_module.cpp
+++ b/gralloc/gralloc_module.cpp
@@ -18,6 +18,7 @@
 
 #include <errno.h>
 #include <pthread.h>
+#include <string.h>
 
 #include <cutils/log.h>
 #include <cutils/atomic.h>