Change CPU target back to pentiumpro

Author: jackpot51

compiler/rustc_target/src/spec/targets/i586_unknown_redox.rs

@@ -2,7 +2,7 @@ use crate::spec::{Cc, LinkerFlavor, Lld, StackProbeType, Target, base};
 
 pub(crate) fn target() -> Target {
     let mut base = base::redox::opts();
-    base.cpu = "pentium".into();
+    base.cpu = "pentiumpro".into();
     base.plt_by_default = false;
     base.max_atomic_width = Some(64);
     base.add_pre_link_args(LinkerFlavor::Gnu(Cc::Yes, Lld::No), &["-m32"]);