Fix windows build of AAPT2

Change-Id: Ib8e1a4322510b582e9600a08d3118842c9abc73c
diff --git a/tools/aapt2/BigBuffer.h b/tools/aapt2/BigBuffer.h
index 025142b..8b6569c 100644
--- a/tools/aapt2/BigBuffer.h
+++ b/tools/aapt2/BigBuffer.h
@@ -17,6 +17,7 @@
 #ifndef AAPT_BIG_BUFFER_H
 #define AAPT_BIG_BUFFER_H
 
+#include <cassert>
 #include <cstring>
 #include <memory>
 #include <vector>