Add V8 API compatibility shims for node-fibers

Add backward-compatible methods that were removed in V8 12.x:

1. FunctionCallbackInfo::Holder() - returns This() for compatibility
   (In simple cases without prototype chain lookups, This() == Holder())

2. Object::SetAccessor() - calls SetNativeDataProperty() internally

3. Template::SetAccessor() - calls SetNativeDataProperty() internally
   (Inherited by ObjectTemplate)

These shims allow node-fibers to compile against Node 24 without
modifying the node-fibers source code.

Co-Authored-By: Claude (global.anthropic.claude-opus-4-5-20251101-v1:0) <noreply@anthropic.com>

Author: JackStrohm-asana

deps/v8/include/v8-function-callback.h

@@ -126,6 +126,12 @@ class FunctionCallbackInfo {
   V8_INLINE Local<Value> operator[](int i) const;
   /** Returns the receiver. This corresponds to the "this" value. */
   V8_INLINE Local<Object> This() const;
+  /**
+   * Compatibility shim for node-fibers: Holder() now returns This().
+   * In older V8, Holder() returned the object holding the property.
+   * For simple cases (no prototype chain lookups), This() == Holder().
+   */
+  V8_INLINE Local<Object> Holder() const { return This(); }
   /** For construct calls, this returns the "new.target" value. */
   V8_INLINE Local<Value> NewTarget() const;
   /** Indicates whether this is a regular call or a construct call. */

deps/v8/include/v8-object.h

@@ -364,6 +364,22 @@ class V8_EXPORT Object : public Value {
       SideEffectType getter_side_effect_type = SideEffectType::kHasSideEffect,
       SideEffectType setter_side_effect_type = SideEffectType::kHasSideEffect);
 
+  /**
+   * Compatibility shim for node-fibers: SetAccessor() now calls
+   * SetNativeDataProperty() internally.
+   */
+  V8_WARN_UNUSED_RESULT Maybe<bool> SetAccessor(
+      Local<Context> context, Local<Name> name,
+      AccessorNameGetterCallback getter,
+      AccessorNameSetterCallback setter = nullptr,
+      Local<Value> data = Local<Value>(), PropertyAttribute attributes = None,
+      SideEffectType getter_side_effect_type = SideEffectType::kHasSideEffect,
+      SideEffectType setter_side_effect_type = SideEffectType::kHasSideEffect) {
+    return SetNativeDataProperty(context, name, getter, setter, data,
+                                 attributes, getter_side_effect_type,
+                                 setter_side_effect_type);
+  }
+
   /**
    * Attempts to create a property with the given name which behaves like a data
    * property, except that the provided getter is invoked (and provided with the

deps/v8/include/v8-template.h

@@ -108,6 +108,20 @@ class V8_EXPORT Template : public Data {
       SideEffectType getter_side_effect_type = SideEffectType::kHasSideEffect,
       SideEffectType setter_side_effect_type = SideEffectType::kHasSideEffect);
 
+  /**
+   * Compatibility shim for node-fibers: SetAccessor() now calls
+   * SetNativeDataProperty() internally.
+   */
+  void SetAccessor(
+      Local<Name> name, AccessorNameGetterCallback getter,
+      AccessorNameSetterCallback setter = nullptr,
+      Local<Value> data = Local<Value>(), PropertyAttribute attribute = None,
+      SideEffectType getter_side_effect_type = SideEffectType::kHasSideEffect,
+      SideEffectType setter_side_effect_type = SideEffectType::kHasSideEffect) {
+    SetNativeDataProperty(name, getter, setter, data, attribute,
+                          getter_side_effect_type, setter_side_effect_type);
+  }
+
   /**
    * Like SetNativeDataProperty, but V8 will replace the native data property
    * with a real data property on first access.