Lit config attempt #2

Author: Sean Olszewski

Tests/Functional/Asynchronous/Use/lit.local.cfg

@@ -1,7 +1,7 @@
 // RUN: %{swiftc} %s -o %T/Use
 // RUN: %T/Use > %t || true
 // RUN: %{xctest_checker} %t %s
-// REQUIRES: OS=macosx
+// REQUIRES: concurrency_runtime
 
 #if os(macOS)
     import SwiftXCTest

Tests/Functional/Asynchronous/Use/main.swift

@@ -0,0 +1,4 @@
+(run_cpu, run_vendor, run_os, run_vers) = re.match('([^-]+)-([^-]+)-([^0-9]+)(.*)', config.variant_triple).groups()
+
+if run_os != 'macosx' or run_vers >= 12:
+    config.available_features.add('concurrency_runtime')