Add missing include.

Test: mm
Bug: None
Change-Id: I8be335ed677e8646d3912ac3db49451bff66eb65
diff --git a/libmemunreachable/Tarjan.h b/libmemunreachable/Tarjan.h
index dcd139a..2546341 100644
--- a/libmemunreachable/Tarjan.h
+++ b/libmemunreachable/Tarjan.h
@@ -19,6 +19,7 @@
 #ifndef LIBMEMUNREACHABLE_TARJAN_H_
 #define LIBMEMUNREACHABLE_TARJAN_H_
 
+#include <assert.h>
 #include <algorithm>
 
 #include "Allocator.h"