[PATCH, 2/4] Enable libstdc++ as a DLL on windows platforms.

[Aaron W. LaFramboise]

Dave Korn wrote:
> Paolo Bonzini wrote:
>> Dave Korn wrote:
>>>   This is patch #2 in the series.  It adds autoconf tests for libstdc++
>>> support wrapper functions present in the Cygwin DLL, and adds an option (only
>>> present for Cygwin and defaulted according to the autoconf test) to make the
>>> compiler invoke the wrappers when linking.
>> If you get agreement for the MinGW guys, this could as well test
>> "cygmin* | pe | mingw*" here and fuse the two case statements (and move
>> everything from cygwin.h to cygming.h or whatever it is called).  This
>> would be preferrable, no?
> 
>   In theory yes, but not until after they have implemented support wrappers in
> the MinGW runtime (these are already present in the latest released Cygwin
> DLL), and they may even decide to take a different approach for their
> platform.  I didn't want to assume they'll be able to do that straight away,
> so I figured that might be the subject of a later patch - when they've got the
> support upstream, they can merge the two cases and move the specs to the
> common file as you suggest.

The complaint I have always had against using ld -wrap for this sort of 
thing is that it takes this command away from the users, as least 
naively.  But this may not be a big deal.

In any case, MinGW doesn't have the wrappers, and we shouldn't block 
this patch (or break i386-pc-mingw32) due to this, especially since this 
is really quite minor.  I would say go ahead with your original patch.

Can you give some advice on exactly how to write the wrappers, and 
exactly how they work?  It would be good to have this documented 
somewhere, if only a paragraph or two on the GCC Wiki.