Implemented basic support for function pointers

examples/thread/thread.q

@@ -0,0 +1,23 @@
+import mem
+import sys
+
+main() {
+	start()
+	start()
+	start()
+	thread()
+}
+
+start() {
+	size := 4096
+	stack := mem.alloc(size)
+	pointer := stack + size - 8
+	store(pointer, 8, thread)
+	sys.clone(0x100 | 0x200 | 0x400 | 0x800 | 0x8000 | 0x10000 | 0x80000000, pointer)
+}
+
+thread() {
+	sys.write(1, "[ ] start\n", 10)
+	sys.write(1, "[x] end\n", 8)
+	sys.exit(0)
+}