build changes

examples/echoserver.monkey

@@ -1,11 +1,12 @@
-#!./monkey-lang
+#!/usr/bin/env monkey-lang
 
 fd := socket("tcp4")
 bind(fd, "0.0.0.0:8000")
 listen(fd, 1)
 
-nfd := accept(fd)
-msg := read(nfd)
-write(nfd, msg)
-close(nfd)
-close(fd)
+while (true) {
+  nfd := accept(fd)
+  msg := read(nfd)
+  write(nfd, msg)
+  close(nfd)
+}