Parallelize singleton execution

Bug: 281536768
Test: manual, presubmits
Change-Id: I57fdc76ba6b277e88e196b506af87127a530fd37
diff --git a/cc/cmakelists.go b/cc/cmakelists.go
index ad130ba..0f3f02d 100644
--- a/cc/cmakelists.go
+++ b/cc/cmakelists.go
@@ -29,7 +29,7 @@
 // structure (see variable CLionOutputProjectsDirectory for root).
 
 func init() {
-	android.RegisterSingletonType("cmakelists_generator", cMakeListsGeneratorSingleton)
+	android.RegisterParallelSingletonType("cmakelists_generator", cMakeListsGeneratorSingleton)
 }
 
 func cMakeListsGeneratorSingleton() android.Singleton {