message: Add SIGABRT to redox
diff: @@ -23,6 +23,7 @@ pub const SIGINT: usize = 2;
  pub const SIGQUIT: usize = 3;
  pub const SIGILL: usize = 4;
  pub const SIGTRAP: usize = 5;
  +pub const SIGABRT: usize = 6;
  pub const SIGBUS: usize = 7;
  pub const SIGFPE: usize = 8;
  pub const SIGKILL: usize = 9;
  