diff --git a/stdlib/public/Synchronization/CMakeLists.txt b/stdlib/public/Synchronization/CMakeLists.txt
index dead46e532bbc..88cc673522ad1 100644
--- a/stdlib/public/Synchronization/CMakeLists.txt
+++ b/stdlib/public/Synchronization/CMakeLists.txt
@@ -33,7 +33,13 @@ set(SWIFT_SYNCHRONIZATION_GYB_SOURCES
   Atomics/AtomicStorage.swift.gyb
 )
 
-# Darwin sources
+# Darwin dependencies and sources
+
+set(SWIFT_SYNCHRONIZATION_DARWIN_DEPENDENCIES)
+
+if(SWIFT_BUILD_SDK_OVERLAY)
+  set(SWIFT_SYNCHRONIZATION_DARWIN_DEPENDENCIES Darwin)
+endif()
 
 set(SWIFT_SYNCHRONIZATION_DARWIN_SOURCES
   Mutex/DarwinImpl.swift
@@ -96,15 +102,17 @@ add_swift_target_library(swiftSynchronization ${SWIFT_STDLIB_LIBRARY_BUILD_TYPES
     Mutex/MutexUnavailable.swift
 
   SWIFT_MODULE_DEPENDS_OSX
-    Darwin
+    ${SWIFT_SYNCHRONIZATION_DARWIN_DEPENDENCIES}
   SWIFT_MODULE_DEPENDS_IOS
-    Darwin
+    ${SWIFT_SYNCHRONIZATION_DARWIN_DEPENDENCIES}
   SWIFT_MODULE_DEPENDS_TVOS
-    Darwin
+    ${SWIFT_SYNCHRONIZATION_DARWIN_DEPENDENCIES}
   SWIFT_MODULE_DEPENDS_WATCHOS
-    Darwin
+    ${SWIFT_SYNCHRONIZATION_DARWIN_DEPENDENCIES}
   SWIFT_MODULE_DEPENDS_XROS
-    Darwin
+    ${SWIFT_SYNCHRONIZATION_DARWIN_DEPENDENCIES}
+  SWIFT_MODULE_DEPENDS_MACCATALYST
+    ${SWIFT_SYNCHRONIZATION_DARWIN_DEPENDENCIES}
   SWIFT_MODULE_DEPENDS_LINUX
     Glibc
   SWIFT_MODULE_DEPENDS_ANDROID