Update getHost methods to also copy host flags, for use in exec->host…

… transitions.

Currently, the exec transition also calls getHost. As currently implemented, this means any host_* options get reset to defaults, instead of what was actually passed. In a further transition to a real host config, the expected set of flags won't be set.

This change fixes getHost so that host_* options are kept, so that exec->host transitions work as expected.

Part of work on execution transitions, bazelbuild#7935.

PiperOrigin-RevId: 248386317

src/main/java/com/google/devtools/build/lib/rules/apple/swift/SwiftCommandLineOptions.java

@@ -45,6 +45,10 @@ public class SwiftCommandLineOptions extends FragmentOptions {
   public FragmentOptions getHost() {
     SwiftCommandLineOptions host = (SwiftCommandLineOptions) super.getHost();
     host.copts = this.hostSwiftcoptList;
+
+    // Save host options in case of a further exec->host transition.
+    host.hostSwiftcoptList = hostSwiftcoptList;
+
     return host;
   }
 }