Fix CQS signal modernize-use-using in fbcode/folly/lang

Reviewed By: dtolnay

Differential Revision: D109004866

fbshipit-source-id: 649206447766b8822a37a12b9749ff671e87ed18

Author: generatedunixname2645487282517272

folly/lang/Exception.cpp

@@ -93,7 +93,7 @@ unsigned int* uncaught_exceptions_ptr() noexcept {
 #if defined(__ia64__) && defined(__hpux__)
 typedef unsigned _Unwind_Ptr __attribute__((__mode__(__word__)));
 #else
-typedef unsigned _Unwind_Ptr __attribute__((__mode__(__pointer__)));
+using _Unwind_Ptr = unsigned long __attribute__((__mode__(__pointer__)));
 #endif
 
 namespace __cxxabiv1 {