Use nio because that somehow makes things work

launcher-dist/build.gradle.kts

@@ -1,4 +1,6 @@
 import io.gitlab.jfronny.scripts.*
+import java.nio.file.Files
+import java.nio.file.Path
 
 plugins {
     id("inceptum.application-standalone")
@@ -118,12 +120,15 @@ jlink {
 if (crosscompile) {
     tasks.jpackage {
         doLast {
-            val src = File("/root/jpackage-out")
-            val trg = buildDir.resolve("jpackage")
-            trg.mkdirs()
-            src.listFiles()!!.forEach {
-                println("Moving $it")
-                it.renameTo(trg.resolve(src.name))
+            val src = Path.of("/root/jpackage-out")
+            val trg = buildDir.resolve("jpackage").toPath()
+            Files.createDirectories(trg)
+            Files.list(src).use {
+                it.filter { Files.isRegularFile(it) }.forEach {
+                    val t = trg.resolve(it.fileName.toString())
+                    println("Moving $it to $t")
+                    Files.move(it, t)
+                }
             }
         }
     }