Workaround: install an older emscripten

.github/workflows/nightly.yml

@@ -62,10 +62,9 @@ jobs:
           - target: cross-arm64-amalgamation
             compiler: gcc
             host_os: ubuntu-24.04
-# Disabled due to https://github.com/emscripten-core/emscripten/issues/22249
-#          - target: emscripten
-#            compiler: emcc
-#            host_os: macos-14
+         - target: emscripten
+           compiler: emcc
+           host_os: macos-14
 
     runs-on: ${{ matrix.host_os }}
 

src/scripts/ci/setup_gh_actions.sh

@@ -140,7 +140,11 @@ else
         boostincdir=$(brew --prefix boost)/include
         echo "BOOST_INCLUDEDIR=$boostincdir" >> "$GITHUB_ENV"
     elif [ "$TARGET" = "emscripten" ]; then
-        brew install emscripten
+        # Workaround: emscripten 3.1.63 is broken, install an older one...
+        brew tap-new botan/local-emscripten
+        brew tap --force homebrew/core
+        brew extract --version=3.1.61 emscripten botan/local-emscripten
+        brew install [email protected]
     fi
 
     if [ -d '/Applications/Xcode_15.3.app/Contents/Developer' ]; then