move Bomb into libunwind, remove dead_code

Author: klensy

src/backtrace/libunwind.rs

@@ -15,7 +15,6 @@
 //!
 //! This is the default unwinding API for all non-Windows platforms currently.
 
-use super::super::Bomb;
 use core::ffi::c_void;
 use core::ptr::addr_of_mut;
 
@@ -100,6 +99,18 @@ impl Clone for Frame {
     }
 }
 
+struct Bomb {
+    enabled: bool,
+}
+
+impl Drop for Bomb {
+    fn drop(&mut self) {
+        if self.enabled {
+            panic!("cannot panic during the backtrace function");
+        }
+    }
+}
+
 #[inline(always)]
 pub unsafe fn trace(mut cb: &mut dyn FnMut(&super::Frame) -> bool) {
     uw::_Unwind_Backtrace(trace_fn, addr_of_mut!(cb).cast());

src/lib.rs

@@ -138,20 +138,6 @@ cfg_if::cfg_if! {
     }
 }
 
-#[allow(dead_code)]
-struct Bomb {
-    enabled: bool,
-}
-
-#[allow(dead_code)]
-impl Drop for Bomb {
-    fn drop(&mut self) {
-        if self.enabled {
-            panic!("cannot panic during the backtrace function");
-        }
-    }
-}
-
 #[allow(dead_code)]
 #[cfg(feature = "std")]
 mod lock {