SwiftUI previews fix

Sources/ApolloCodegenLib/ApolloCLI.swift

@@ -1,7 +1,9 @@
 import Foundation
 
+// Only available on macOS
+#if os(macOS)
+
 /// Wrapper for calling the bundled node-based Apollo CLI.
-@available(OSX, message: "Only available on macOS")
 public struct ApolloCLI {
 
   /// Creates an instance of `ApolloCLI`, downloading and extracting if needed
@@ -47,3 +49,5 @@ public struct ApolloCLI {
     return try Basher.run(command: command, from: folder)
   }
 }
+
+#endif

Sources/ApolloCodegenLib/ApolloCodegen.swift

@@ -1,7 +1,9 @@
 import Foundation
 
+// Only available on macOS
+#if os(macOS)
+
 /// A class to facilitate running code generation
-@available(OSX, message: "Only available on macOS")
 public class ApolloCodegen {
 
   /// Errors which can happen with code generation
@@ -42,3 +44,5 @@ public class ApolloCodegen {
     return try cli.runApollo(with: options.arguments, from: folder)
   }
 }
+
+#endif

Sources/ApolloCodegenLib/ApolloSchemaDownloader.swift

@@ -1,7 +1,9 @@
 import Foundation
 
+// Only available on macOS
+#if os(macOS)
+
 /// A wrapper to facilitate downloading a schema with the Apollo node CLI
-@available(OSX, message: "Only available on macOS")
 public struct ApolloSchemaDownloader {
 
   /// Runs code generation from the given folder with the passed-in options
@@ -19,3 +21,5 @@ public struct ApolloSchemaDownloader {
     return try cli.runApollo(with: options.arguments)
   }
 }
+
+#endif

Sources/ApolloCodegenLib/Basher.swift

@@ -1,7 +1,9 @@
 import Foundation
 
+// Only available on macOS
+#if os(macOS)
+
 /// Bash command runner
-@available(OSX, message: "Only available on macOS")
 public struct Basher {
 
   public enum BashError: Error, LocalizedError {
@@ -65,3 +67,5 @@ public struct Basher {
     return output
   }
 }
+
+#endif

Sources/ApolloCodegenLib/CLIDownloader.swift

@@ -1,7 +1,9 @@
 import Foundation
 
+// Only available on macOS
+#if os(macOS)
+
 /// Helper for downloading the CLI Zip file so we don't have to include it in the repo.
-@available(OSX, message: "Only available on macOS")
 struct CLIDownloader {
 
   enum CLIDownloaderError: Error, LocalizedError {
@@ -118,3 +120,5 @@ struct CLIDownloader {
     }
   }
 }
+
+#endif

Sources/ApolloCodegenLib/CLIExtractor.swift

@@ -1,7 +1,9 @@
 import Foundation
 
+// Only available on macOS
+#if os(macOS)
+
 /// Helper for extracting and validating the node-based Apollo CLI from a zip.
-@available(OSX, message: "Only available on macOS")
 struct CLIExtractor {
 
   // MARK: - Extracting the binary
@@ -122,3 +124,5 @@ struct CLIExtractor {
     }
   }
 }
+
+#endif