Include strings.h for the strcasecmp prototype.

Change-Id: I0659ce2186547274e58f8b2027e16d3e45189353
diff --git a/libs/utils/AssetManager.cpp b/libs/utils/AssetManager.cpp
index e09e755..6e57d93d 100644
--- a/libs/utils/AssetManager.cpp
+++ b/libs/utils/AssetManager.cpp
@@ -36,6 +36,7 @@
 #include <dirent.h>
 #include <errno.h>
 #include <assert.h>
+#include <strings.h>
 
 using namespace android;
 
@@ -1764,4 +1765,3 @@
 
     return mZipPath.size()-1;
 }
-