CI: Fix emscripten builds that broke due behavior change of emscripten SDK.
diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index 8edef47..b3b910f 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -394,7 +394,9 @@
 
     - name: Build example_emscripten
       run: |
-        source emsdk-master/emsdk_env.sh
+        pushd emsdk-master
+        source ./emsdk_env.sh
+        popd
         make -C examples/example_emscripten
 
   Static-Analysis: