cast size_t to unsigned long, not unsigned (even though there is no risk of truncation here, it's still better practice)

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@43965 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/unix/stackwalk.cpp

@@ -254,7 +254,8 @@ int wxStackWalker::InitFrames(wxStackFrame *arr, size_t n, void **addresses, cha
         }
         else
         {
-            wxLogDebug(_T("cannot read addr2line output for %u-th stack frame!"), unsigned(i));
+            wxLogDebug(_T("cannot read addr2line output for stack frame #%lu"),
+                       (unsigned long)i);
             return false;
         }