compiler: enable unwinding on riscv32imac_unknown_xous_elf

Now that everything is in place to support unwinding on Xous, enable
this for that target.

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

Author: xobs

compiler/rustc_target/src/spec/riscv32imac_unknown_xous_elf.rs

@@ -14,7 +14,7 @@ pub fn target() -> Target {
             cpu: "generic-rv32".into(),
             max_atomic_width: Some(32),
             features: "+m,+a,+c".into(),
-            panic_strategy: PanicStrategy::Abort,
+            panic_strategy: PanicStrategy::Unwind,
             relocation_model: RelocModel::Static,
             ..Default::default()
         },