[patch PR libstdc++/51135]: Fix [4.7 Regression] SIGSEGV during exception cleanup on win32

[Paolo Carlini]

Hi,
> On Mon, 12 Dec 2011, Kai Tietz wrote:
>
>> Index: gcc/libstdc++-v3/libsupc++/cxxabi.h
>> ===================================================================
>> --- gcc.orig/libstdc++-v3/libsupc++/cxxabi.h
>> +++ gcc/libstdc++-v3/libsupc++/cxxabi.h
>> @@ -51,6 +51,10 @@
>> #include <bits/cxxabi_tweaks.h>
>> #include <bits/cxxabi_forced.h>
>>
>> +#ifndef _GLIBCXX_USE_THISCALL_ON_DTOR
>> +typedef void (*__cxa_dtor_type) (void *);
>> +#endif
>> +
>
> This changes the type from a function with "C" linkage to one with 
> "C++" linkage, is that on purpose?
Humm, thanks, I didn't really spend time on what was going on *below* 
the define, only to the right way to implement the mingw specific bits. 
I guess moving the #ifndef a few lines down, close to the other typedef 
should be the safe thing to do. That also requires adjustment in the 
config files, the typedef there must be also wrapped in #ifdef 
__cplusplus, etc.

Please do the Change Kai.
> There is a type __cxa_cdtor_type a couple lines below, which also 
> seems used for destructors, but that one doesn't get __thiscall, 
> that's confusing (but then there's probably a reason why it wasn't 
> used in __cxa_throw).
No idea if it's right for mingw.

Paolo.