diff --git a/web/Makefile b/web/Makefile
index 3b80e49..96ea01f 100644
--- a/web/Makefile
+++ b/web/Makefile
@@ -3,11 +3,11 @@ release/SignalsmithStretch.mjs: release/SignalsmithStretch.js
 	@ cat release/SignalsmithStretch.js >> release/SignalsmithStretch.mjs
 	@ echo "let _export=SignalsmithStretch;export default _export;" >> release/SignalsmithStretch.mjs
 
-release/SignalsmithStretch.js: emscripten/main.js web-wrapper.js ../signalsmith-stretch.h
+release/SignalsmithStretch.js: emscripten/main.js web-wrapper.js
 	@ cp emscripten/main.js release/SignalsmithStretch.js
 	@ cat web-wrapper.js >> release/SignalsmithStretch.js
 
-emscripten/main.js: emscripten/main.cpp
+emscripten/main.js: emscripten/main.cpp ../signalsmith-stretch.h
 	@ emscripten/compile.sh emscripten/main.cpp emscripten/main.js SignalsmithStretch
 
 ## Development helpers