CUPS will pass a / in the proposed filename where the original filena…

…me on disk contains a : (which Finder displays as /)

So we need to replace the / with a :

pdfwriter/main.swift

@@ -74,7 +74,7 @@ if !FileManager.default.fileExists(atPath: outDir, isDirectory: &isDir) {
     chown(outDir, passwd.pw_uid, passwd.pw_gid)
 }
 
-var fileName = (CommandLine.arguments[3] as NSString).deletingPathExtension
+var fileName = (CommandLine.arguments[3].replacingOccurrences(of:"/", with: ":") as NSString).deletingPathExtension
 if fileName == "(stdin)" {fileName = "Untitled" }
 
 // make sure we have a unique filename