Merge fix-7.3.7 to master (#2203)

* Fix build issue in older versions of USD (#2199)

* Fix build issue in older versions of USD (#2199) (#2200)

* more fixes for older USD versions

* expose legacy delegate Stop() declaration

---------

Co-authored-by: Ashley Handscomb Retallack <ashley.handscomb.retallack@autodesk.com>

libs/render_delegate/render_delegate.cpp

@@ -1670,7 +1670,11 @@ bool HdArnoldRenderDelegate::IsPauseSupported() const { return false; }
 
 bool HdArnoldRenderDelegate::IsStopSupported() const { return true; }
 
+#if PXR_VERSION >= 2203
 bool HdArnoldRenderDelegate::Stop(bool blocking)
+#else
+bool HdArnoldRenderDelegate::Stop()
+#endif
 {
     _renderParam->Pause();
     return true;
@@ -1688,11 +1692,13 @@ bool HdArnoldRenderDelegate::Restart()
     return true;
 }
 
+#if PXR_VERSION >= 2203
 bool HdArnoldRenderDelegate::IsStopped() const
 {   
     int status = AiRenderGetStatus(GetRenderSession());
     return (status != AI_RENDER_STATUS_RENDERING && status != AI_RENDER_STATUS_RESTARTING);
 }
+#endif
 
 const HdArnoldRenderDelegate::NativeRprimParamList* HdArnoldRenderDelegate::GetNativeRprimParamList(
     const AtString& arnoldNodeType) const

libs/render_delegate/render_delegate.h

@@ -367,17 +367,23 @@ class HdArnoldRenderDelegate final : public HdRenderDelegate {
     HDARNOLD_API
     bool IsStopSupported() const override;
 
+#if PXR_VERSION >= 2203
     /// Advertise whether the render was stopped or if it's in progress
     /// @return True if no render is in progress
     HDARNOLD_API
     bool IsStopped() const override;
+#endif
 
+#if PXR_VERSION >= 2203
     /// Stop all of this delegate's background rendering threads. Default
     /// implementation does nothing.
     ///
     /// @return True if successful.
     HDARNOLD_API
     bool Stop(bool blocking = true) override;
+#else
+    bool Stop() override;
+#endif
 
     /// Restart all of this delegate's background rendering threads previously
     /// paused by a call to Stop. Default implementation does nothing.

libs/render_delegate/rprim.h

@@ -77,12 +77,14 @@ class HdArnoldRprim : public HydraType {
     /// @return Pointer to the Render Delegate.
     HdArnoldRenderDelegate* GetRenderDelegate() { return _renderDelegate; }
 
+#if PXR_VERSION >= 2203
     /// Tracking render tag changes
     void UpdateRenderTag(HdSceneDelegate *delegate, HdRenderParam *renderParam) override {
         HdRprim::UpdateRenderTag(delegate, renderParam);
         HdArnoldRenderParamInterrupt param(renderParam);
         _shape.UpdateRenderTag(this, delegate, param);
     }
+#endif
 
     /// Syncs internal data and arnold state with hydra.
     void SyncShape(