diff --git a/cmake/modules/shared/AvailabilityDefinitions.cmake b/cmake/modules/shared/AvailabilityDefinitions.cmake
index e7595f22..24e186ae 100644
--- a/cmake/modules/shared/AvailabilityDefinitions.cmake
+++ b/cmake/modules/shared/AvailabilityDefinitions.cmake
@@ -13,4 +13,5 @@ add_compile_options(
   "SHELL:$<$<COMPILE_LANGUAGE:Swift>:-Xfrontend -define-availability -Xfrontend \"_clockAPI:macOS 13.0, iOS 16.0, watchOS 9.0, tvOS 16.0\">"
   "SHELL:$<$<COMPILE_LANGUAGE:Swift>:-Xfrontend -define-availability -Xfrontend \"_regexAPI:macOS 13.0, iOS 16.0, tvOS 16.0, watchOS 9.0\">"
   "SHELL:$<$<COMPILE_LANGUAGE:Swift>:-Xfrontend -define-availability -Xfrontend \"_swiftVersionAPI:macOS 13.0, iOS 16.0, tvOS 16.0, watchOS 9.0\">"
+  "SHELL:$<$<COMPILE_LANGUAGE:Swift>:-Xfrontend -define-availability -Xfrontend \"_synchronizationAPI:macOS 15.0, iOS 18.0, watchOS 11.0, tvOS 18.0, visionOS 2.0\">"
   "SHELL:$<$<COMPILE_LANGUAGE:Swift>:-Xfrontend -define-availability -Xfrontend \"_distantFuture:macOS 99.0, iOS 99.0, watchOS 99.0, tvOS 99.0, visionOS 99.0\">")