Use the default xcode version & fix emsripten build

.github/workflows/build.yml

@@ -374,15 +374,6 @@ jobs:
         with:
           toolchain: 1.95.0
           targets: aarch64-apple-ios-sim
-      # GitHub recommends explicitly selecting the desired Xcode version:
-      # https://github.com/actions/runner-images/issues/12541#issuecomment-3083850140
-      # This became a necessity as a result of
-      # https://github.com/actions/runner-images/issues/12541 and
-      # https://github.com/actions/runner-images/issues/12751.
-      - name: Select Xcode version
-        run: |
-          sudo xcode-select --switch /Applications/Xcode_16.4.app
-
       - name: Build and test
         run: python3 Platforms/Apple ci iOS --fast-ci
 

.github/workflows/reusable-emscripten.yml

@@ -55,6 +55,10 @@ jobs:
       uses: actions/setup-python@a309ff8b426b58ec0e2a45f0f869d46889d02405 # v6.2.0
       with:
         python-version: '3.x'
+    - uses: dtolnay/rust-toolchain@f133eefe930d61f0d9371efd474daf0125ed3dd1 # 1.95.0
+      with:
+        toolchain: 1.95.0
+        targets: wasm32-unknown-emscripten
     - name: "Runner image version"
       run: echo "IMAGE_OS_VERSION=${ImageOS}-${ImageVersion}" >> "$GITHUB_ENV"
     - name: "Install Emscripten"

Modules/cpython-sys/build.rs

@@ -38,6 +38,7 @@ fn emit_rerun_instructions(builddir: Option<&str>) {
         "PY_CFLAGS",
         "TARGET",
         "WASI_SDK_PATH",
+        "EMSDK",
     ] {
         println!("cargo:rerun-if-env-changed={var}");
     }
@@ -227,6 +228,21 @@ fn generate_c_api_bindings(
         }
     }
 
+    if !have_sysroot
+        && cargo_target.contains("emscripten")
+        && let Ok(emsdk) = env::var("EMSDK")
+    {
+        let sysroot = PathBuf::from(&emsdk)
+            .join("upstream")
+            .join("emscripten")
+            .join("cache")
+            .join("sysroot");
+        if sysroot.is_dir() {
+            builder = builder.clang_arg(format!("--sysroot={}", sysroot.display()));
+            have_sysroot = true;
+        }
+    }
+
     // Android NDK: ANDROID_HOME is set by the CI/user environment, and
     // Android/android-env.sh sets CC to the NDK clang binary at:
     //   $ANDROID_HOME/ndk/<ver>/toolchains/llvm/prebuilt/<host>/bin/<triple>-clang

configure.ac

@@ -2410,6 +2410,7 @@ AS_CASE([$ac_sys_system],
 
     dnl map int64_t and uint64_t to JS bigint
     AS_VAR_APPEND([LDFLAGS_NODIST], [" -sWASM_BIGINT"])
+    AS_VAR_APPEND([LDFLAGS_NODIST], [" -fwasm-exceptions"])
 
     dnl Include file system support
     AS_VAR_APPEND([LINKFORSHARED], [" -sFORCE_FILESYSTEM -lidbfs.js -lnodefs.js -lproxyfs.js -lworkerfs.js"])