Fix weird linker issues.

c++/src/kj/async-inl.h

@@ -551,15 +551,11 @@ template <>
 class ArrayJoinPromiseNode<void> final: public ArrayJoinPromiseNodeBase {
 public:
   ArrayJoinPromiseNode(Array<Own<PromiseNode>> promises,
-                       Array<ExceptionOr<_::Void>> resultParts)
-      : ArrayJoinPromiseNodeBase(
-            kj::mv(promises), resultParts.begin(), sizeof(ExceptionOr<_::Void>)),
-        resultParts(kj::mv(resultParts)) {}
+                       Array<ExceptionOr<_::Void>> resultParts);
+  ~ArrayJoinPromiseNode();
 
 protected:
-  void getNoError(ExceptionOrValue& output) noexcept override {
-    output.as<_::Void>() = _::Void();
-  }
+  void getNoError(ExceptionOrValue& output) noexcept override;
 
 private:
   Array<ExceptionOr<_::Void>> resultParts;
@@ -776,12 +772,6 @@ Promise<Array<T>> joinPromises(Array<Promise<T>>&& promises) {
       heapArray<_::ExceptionOr<T>>(promises.size())));
 }
 
-inline Promise<void> joinPromises(Array<Promise<void>>&& promises) {
-  return Promise<void>(false, kj::heap<_::ArrayJoinPromiseNode<void>>(
-      KJ_MAP(p, promises) { return kj::mv(p.node); },
-      heapArray<_::ExceptionOr<_::Void>>(promises.size())));
-}
-
 // =======================================================================================
 
 namespace _ {  // private

c++/src/kj/async.c++

@@ -885,6 +885,27 @@ Maybe<Exception> ArrayJoinPromiseNodeBase::Branch::getPart() {
   return kj::mv(output.exception);
 }
 
+ArrayJoinPromiseNode<void>::ArrayJoinPromiseNode(
+    Array<Own<PromiseNode>> promises, Array<ExceptionOr<_::Void>> resultParts)
+    : ArrayJoinPromiseNodeBase(kj::mv(promises), resultParts.begin(), sizeof(ExceptionOr<_::Void>)),
+      resultParts(kj::mv(resultParts)) {}
+
+ArrayJoinPromiseNode<void>::~ArrayJoinPromiseNode() {}
+
+void ArrayJoinPromiseNode<void>::getNoError(ExceptionOrValue& output) noexcept {
+  output.as<_::Void>() = _::Void();
+}
+
+}  // namespace _ (private)
+
+Promise<void> joinPromises(Array<Promise<void>>&& promises) {
+  return Promise<void>(false, kj::heap<_::ArrayJoinPromiseNode<void>>(
+      KJ_MAP(p, promises) { return kj::mv(p.node); },
+      heapArray<_::ExceptionOr<_::Void>>(promises.size())));
+}
+
+namespace _ {  // (private)
+
 // -------------------------------------------------------------------
 
 EagerPromiseNodeBase::EagerPromiseNodeBase(