xous: fix unwinding and unused symbol errors

The unwinding feature is called `panic-unwind` and not `panic_unwind`.
Adjust the feature gate to look for these values.

Additionally, the `abort_internal()` call is no longer used.

Signed-off-by: Sean Cross <sean@xobs.io>

library/std/src/sys/pal/xous/mod.rs

@@ -1,14 +1,8 @@
 #![forbid(unsafe_op_in_unsafe_fn)]
 
-use crate::os::xous::ffi::exit;
-
 pub mod os;
 pub mod time;
 
 #[path = "../unsupported/common.rs"]
 mod common;
 pub use common::*;
-
-pub fn abort_internal() -> ! {
-    exit(101);
-}

library/std/src/sys/pal/xous/os.rs

@@ -11,7 +11,7 @@
 static PARAMS_ADDRESS: Atomic<*mut u8> = AtomicPtr::new(core::ptr::null_mut());
 
 #[cfg(not(test))]
-#[cfg(feature = "panic_unwind")]
+#[cfg(feature = "panic-unwind")]
 mod eh_unwinding {
     pub(crate) struct EhFrameFinder;
     pub(crate) static mut EH_FRAME_ADDRESS: usize = 0;
@@ -45,7 +45,7 @@ pub extern "C" fn abort() {
 
     #[unsafe(no_mangle)]
     pub extern "C" fn _start(eh_frame: usize, params_address: usize) {
-        #[cfg(feature = "panic_unwind")]
+        #[cfg(feature = "panic-unwind")]
         {
             unsafe { super::eh_unwinding::EH_FRAME_ADDRESS = eh_frame };
             unwind::set_custom_eh_frame_finder(&super::eh_unwinding::EH_FRAME_SETTINGS).ok();