Fix errors on non-x86_64.

redox-rt/src/arch/aarch64.rs

@@ -23,6 +23,7 @@ pub struct SigArea {
     pub onstack: u64,
     pub disable_signals_depth: u64,
     pub pctl: usize, // TODO: remove
+    pub last_sig_was_restart: bool,
 }
 #[repr(C)]
 #[derive(Debug, Default)]

redox-rt/src/arch/i686.rs

@@ -21,6 +21,7 @@ pub struct SigArea {
     pub tmp_eax: usize,
     pub tmp_edx: usize,
     pub disable_signals_depth: u64,
+    pub last_sig_was_restart: bool,
 }
 #[derive(Debug, Default)]
 #[repr(C, align(16))]