diff --git a/src/unpack.cpp b/src/unpack.cpp
index b8bddac..a2ad2ab 100644
--- a/src/unpack.cpp
+++ b/src/unpack.cpp
@@ -10,7 +10,7 @@
 #include <cstdio>
 #include <cmath>
 
-#ifdef EMSCRIPTEN
+#ifdef __EMSCRIPTEN__
 # include <emscripten.h>
 #endif