CI: Fixes WGPU example build.
diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index 45688c4..c77e9a8 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -494,7 +494,7 @@
         pushd emsdk-master
         source ./emsdk_env.sh
         popd
-        make -C examples/example_emscripten_wgpu
+        make -C examples/example_emscripten_wgpu -f Makefile.emscripten
 
   Android:
     runs-on: ubuntu-22.04