update to emscripten 3.1.61 (#860)

.github/workflows/manifold.yml

@@ -123,8 +123,8 @@ jobs:
         # setup emscripten
         git clone https://github.com/emscripten-core/emsdk.git
         cd emsdk
-        ./emsdk install 3.1.45
-        ./emsdk activate 3.1.45
+        ./emsdk install 3.1.61
+        ./emsdk activate 3.1.61
     - uses: jwlawson/actions-setup-cmake@v2
     - name: Build WASM
       run: |

src/utilities/include/hashtable.h

@@ -132,10 +132,9 @@ class HashTable {
         step_(step) {}
 
   HashTable(const HashTable& other)
-      : keys_(other.keys_),
-        values_(other.values_),
-        used_(other.used_),
-        step_(other.step_) {}
+      : keys_(other.keys_), values_(other.values_), step_(other.step_) {
+    used_.store(other.used_.load());
+  }
 
   HashTable& operator=(const HashTable& other) {
     if (this == &other) return *this;