Re: [patch libstdc++]: Add some missing errno-constants for mingw-targets

[Paolo Carlini <paolo dot carlini at oracle dot com>]

Hi,
> Ah, now I got you.  Hmm, well, I see here no advantage in adding
> another macro to check for an macro.  As in code of libstdc++ there is
> actual no use for those new ones.
To be clear, I didn't personally invent those, but I'm still finding a 
bit strange doing only for mingw something completely different, 
considering in particular that the autoconf procedure is run *anyway* on 
mingw too...
> Nevertheless, for some error-numbers (eg. EAFNOSUPPORT, EBADMSG, etc)
> - which are socket API related - there is no constant define in
> errno.h (and never will be).  So code to emulate this would be still a
> manual thing in error_constants.h header AFAICS (if we plan to support
> them for mingw targets).
Once more, I don't understand: didn't you suggest changing *only* ENOSPC 
and EPERM? Why are we now discussing other error-numbers like ECHILD, 
EAFNOSUPPORT and EBADMSG? Are the latter defined in errno.h? In that 
case, please use [GLIBCXX_CHECK_SYSTEM_ERROR] for now. We can always 
simplify things at a later time.

Paolo.