Re: stdnoreturn: fix for Cygwin

[Eric Blake <eblake@redhat.com>]

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On 08/16/2017 07:59 PM, Eric Blake wrote:
> Adding cygwin list...
> 
> On 08/16/2017 07:01 PM, Bruno Haible wrote:
>> On Cygwin 1.7.30, I'm seeing this testdir build failure, when compiling
>> test-stdnoreturn.c:
>>
>> /usr/include/stdlib.h:66:28: error: expected ‘,’ or ‘;’ before ‘)’ token
>>  _VOID _EXFUN(abort,(_VOID) _ATTRIBUTE ((noreturn)));
> 
>> +
>> +   Similarly, on Cygwin, standard include files contain declarations like
>> +     void __cdecl abort (void) __attribute__ ((noreturn));
>> +   "#define noreturn _Noreturn" would cause this declaration to be rewritten
>> +   to the invalid
>> +     void __cdecl abort (void) __attribute__ ((__attribute__ ((__noreturn__))));
> 
> Hmm. It's evil for any system .h file to ever use
> __attribute__((barename)), since barename is in the user's namespace and
> can therefore be defined to anything else, possibly breaking the header
> (as you just proved).  Hopefully, the problem goes away if cygwin
> patches its headers to use __attribute__((__noreturn__)), so that gnulib
> can then define noreturn at will.
> 
> I'll look into patching Cygwin to fix all barename attributes I can find
> that should be __barename__ instead.

On a closer look, I've already done this, several years ago (although a
few more have crept in since then):
https://cygwin.com/git/gitweb.cgi?p=newlib-cygwin.git;a=commitdiff;h=ada456dcf

Bruno, your cygwin installation of 1.7.30 is old, compared to current 2.8.2

-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3266
Virtualization:  qemu.org | libvirt.org


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