std: personality: support gcc personality on Xous

Xous as an operating system is compiled with gcc-type personalities when
it comes to unwinding. This enables unwinding inside panics on Xous,
which enables Rust tests.

Signed-off-by: Sean Cross <[email protected]>

Author: xobs

library/std/src/sys/personality/mod.rs

@@ -28,6 +28,7 @@ cfg_if::cfg_if! {
     } else if #[cfg(any(
         all(target_family = "windows", target_env = "gnu"),
         target_os = "psp",
+        target_os = "xous",
         target_os = "solid_asp3",
         all(target_family = "unix", not(target_os = "espidf"), not(target_os = "l4re")),
         all(target_vendor = "fortanix", target_env = "sgx"),