Fix breakage on Windows, which doesn't have ProcessResult.ExitStatus.signalled.

Author: abertelrud

Sources/Workspace/DefaultPluginScriptRunner.swift

@@ -247,8 +247,10 @@ public struct DefaultPluginScriptRunner: PluginScriptRunner, Cancellable {
                     switch processExitStatus {
                     case .terminated(let code):
                         self = .exit(code: code)
+                    #if !os(Windows)
                     case .signalled(let signal):
                         self = .signal(number: signal)
+                    #endif
                     }
                 }
             }