Added basic threading support, changed license back to Apache-2.0 and many fixes. (0.15.0)

examples/threads_demo.fun

@@ -0,0 +1,62 @@
+#!/usr/bin/env fun
+
+/*
+ * This file is part of the Fun programming language.
+ * https://hanez.org/project/fun/
+ *
+ * Copyright 2025 Johannes Findeisen <you@hanez.org>
+ * Licensed under the terms of the Apache-2.0 license.
+ * https://opensource.org/license/apache-2-0
+ *
+ * Added: 2025-09-30
+ */
+
+// Threading demo for Fun
+// Run without installing:
+//   FUN_LIB_DIR="$(pwd)/lib" ./build/fun examples/threads_demo.fun
+//   (Windows PowerShell) $env:FUN_LIB_DIR="$PWD\lib"; .\build\fun.exe examples\threads_demo.fun
+
+print("=== Threads demo ===")
+
+// A worker function that does some work and returns a value
+fun square(n)
+  // simulate work
+  sleep(100)
+  return n * n
+
+// Spawn several workers
+ids = []
+for x in [1, 2, 3, 4, 5]
+  id = thread_spawn(square, x)   // pass a single argument
+  push(ids, id)
+  print("spawned thread id=" + to_string(id) + " for x=" + to_string(x))
+
+print("Joining threads...")
+results = []
+for id in ids
+  r = thread_join(id)
+  push(results, r)
+
+print("Squares: " + to_string(results))
+
+// Example: pass multiple args via array
+fun add3(a, b, c)
+  return a + b + c
+
+tid = thread_spawn(add3, [10, 20, 30])
+print("join add3 -> " + to_string(thread_join(tid)))
+
+print("=== Threads demo done ===")
+
+/* Expected output:
+=== Threads demo ===
+spawned thread id=1 for x=1
+spawned thread id=2 for x=2
+spawned thread id=3 for x=3
+spawned thread id=4 for x=4
+spawned thread id=5 for x=5
+Joining threads...
+Squares: [array n=5]
+join add3 -> 60
+=== Threads demo done ===
+*/