[iOS] Follow up commit to fix use of macOS specific vsync control.

Obj-C method 'setDisplaySyncEnabled' is only available in CAMetalLayer on macOS, not on iOS.
Use old method of default preferred frame rate for iOS swap-chain.

sources/Renderer/Metal/MTSwapChain.mm

@@ -113,24 +113,36 @@ - (void)mtkView:(nonnull MTKView *)view drawableSizeWillChange:(CGSize)size
  return (&renderPass_);
 }
 
+static NSInteger GetPrimaryDisplayRefreshRate()
+{
+ constexpr NSInteger defaultRefreshRate = 60;
+ if (const Display* display = Display::GetPrimary())
+ return static_cast<NSInteger>(display->GetDisplayMode().refreshRate);
+ else
+ return defaultRefreshRate;
+}
+
 bool MTSwapChain::SetVsyncInterval(std::uint32_t vsyncInterval)
 {
- static const NSInteger defaultRefreshRate = 60;
  if (vsyncInterval > 0)
  {
- /* Apply v-sync interval to display refresh rate */
- if (auto display = Display::GetPrimary())
- view_.preferredFramesPerSecond = static_cast<NSInteger>(display->GetDisplayMode().refreshRate / vsyncInterval);
- else
- view_.preferredFramesPerSecond = defaultRefreshRate / static_cast<NSInteger>(vsyncInterval);
-
+ #ifdef LLGL_OS_MACOS
  /* Enable display sync in CAMetalLayer */
  [(CAMetalLayer*)[view_ layer] setDisplaySyncEnabled:YES];
+ #endif
+
+ /* Apply v-sync interval to display refresh rate */
+ view_.preferredFramesPerSecond = GetPrimaryDisplayRefreshRate() / static_cast<NSInteger>(vsyncInterval);
  }
  else
  {
+ #ifdef LLGL_OS_MACOS
  /* Disable display sync in CAMetalLayer */
  [(CAMetalLayer*)[view_ layer] setDisplaySyncEnabled:NO];
+ #else
+ /* Set preferred frame rate to default value */
+ view_.preferredFramesPerSecond = GetPrimaryDisplayRefreshRate();
+ #endif
  }
  return true;
 }