More work to make libRS buildable on the host.

Change-Id: I239585ef7c1334f7fc19fa6423535dea7b9a753f
diff --git a/rsScriptC.h b/rsScriptC.h
index 4c85745..5c191d9 100644
--- a/rsScriptC.h
+++ b/rsScriptC.h
@@ -39,7 +39,7 @@
     const Allocation *ptrToAllocation(const void *) const;
 
 
-    virtual void Invoke(Context *rsc, uint32_t slot, const void *data, uint32_t len);
+    virtual void Invoke(Context *rsc, uint32_t slot, const void *data, size_t len);
 
     virtual uint32_t run(Context *);