use @main instead of top-level code

This commit renames main.swift to Generator.swift, which is necessary to use the @main annotation.

This commit attaches the @main annotation to GeneratorCommand and
removes the top-level code that used a DispatchSemaphore hack to wait
synchronously for an async to finish.

Generator/Generator/main.swift → Generator/Generator/Generator.swift

@@ -47,6 +47,7 @@ let generateResettableCache = false
 //skipList.insert("OpenXRInterface")
 //#endif
 
+@main
 struct GeneratorCommand: AsyncParsableCommand {
     @Flag(
         help: "Generator all output to a single Swift file. Possibly useful on Windows."
@@ -205,12 +206,3 @@ struct Generator {
         }
     }
 }
-
-let semaphore = DispatchSemaphore(value: 0)
-let _ = Task {
-    defer { semaphore.signal() }
-    await GeneratorCommand.main()
-}
-semaphore.wait()
-
-//print ("Done")

Package.swift

@@ -90,7 +90,9 @@ var targets: [Target] = [
         exclude: ["README.md"],
         swiftSettings: [
             // Uncomment for using legacy array-based marshalling
-            //.define("LEGACY_MARSHALING")
+            //.define("LEGACY_MARSHALING"),
+
+            //.enableExperimentalFeature("StrictConcurrency"),
         ]
     ),