Merge branch 'SI_QUEUE' into 'master'

Remove SI_QUEUE and SI_USER from signal mod.rs

See merge request redox-os/relibc!933

src/header/signal/mod.rs

@@ -45,9 +45,6 @@ pub const SIG_BLOCK: c_int = 0;
 pub const SIG_UNBLOCK: c_int = 1;
 pub const SIG_SETMASK: c_int = 2;
 
-pub const SI_QUEUE: c_int = -1;
-pub const SI_USER: c_int = 0;
-
 pub const SIGEV_SIGNAL: c_int = 0;
 pub const SIGEV_NONE: c_int = 1;
 pub const SIGEV_THREAD: c_int = 2;