create_process unable to find executable after chroot

Imported from http://bugzilla.roxen.com/bugzilla/show_bug.cgi?id=3613

Reported by Thomas Bopp, Uni-GH Paderborn astra@upb.de

The following does not work. There is a test file with exec permissions /root/test and removing the chroot line will make it work. It also fails with any other combination of PATH, /root/test, cwd, etc.

void main()
{
  mapping env = getenv();
  System.chroot("/root");
  env["PATH"] = "/:/root/";
  mapping options = ([
    "stdin":Stdio.stdin,
    "stdout":Stdio.stdout,
    "env": env,
  ]);
  Process.create_process( ({ "test" }), options );
}