Take @compnerd's suggestion

Co-authored-by: Saleem Abdulrasool <[email protected]>

Author: dabrahams

CMakeLists.txt

@@ -17,9 +17,13 @@ set(CMAKE_Swift_MODULE_DIRECTORY ${CMAKE_BINARY_DIR}/swift)
 include(CTest)
 include(SwiftSupport)
 
-find_package(dispatch QUIET CONFIG)
-find_package(Foundation QUIET CONFIG)
-find_package(XCTest QUIET CONFIG)
+if(NOT APPLE)
+  find_package(dispatch CONFIG)
+  find_package(Foundation CONFIG)
+  if(BUILD_TESTING)
+    find_package(XCTest CONFIG)
+  endif()
+endif()
 
 add_subdirectory(Sources)
 if(BUILD_EXAMPLES)