Use less sussy cast

Author: workingjubilee

tests/skip_inner_frames.rs

@@ -1,4 +1,5 @@
 use backtrace::Backtrace;
+use core::ffi::c_void;
 
 // This test only works on platforms which have a working `symbol_address`
 // function for frames which reports the starting address of a symbol. As a
@@ -22,9 +23,9 @@ fn backtrace_new_unresolved_should_start_with_call_site_trace() {
 
     assert!(!b.frames().is_empty());
 
-    let this_ip = backtrace_new_unresolved_should_start_with_call_site_trace as usize;
-    println!("this_ip: {:?}", this_ip as *const usize);
-    let frame_ip = b.frames().first().unwrap().symbol_address() as usize;
+    let this_ip = backtrace_new_unresolved_should_start_with_call_site_trace as *mut c_void;
+    println!("this_ip: {:p}", this_ip);
+    let frame_ip = b.frames().first().unwrap().symbol_address();
     assert_eq!(this_ip, frame_ip);
 }