building libpng-1.6.29 fails with error in signal.h

Yaakov Selkowitz
Tue Jul 4 23:16:00 GMT 2017

On 2017-07-04 15:46, Marco Atzeri wrote:
> On 04/07/2017 20:59, Denis Excoffier wrote:
>> I tried to compile libpng-1.6.29 and failed at first. I obtain:
>> /usr/include/cygwin/signal.h:328:34: error: unknown type name 'siginfo_t'
>>      void  (*sa_sigaction) ( int, siginfo_t *, void * );
>>                                   ^
>> I really don't know which (signal.h or libpng) is okay (or none). Will 
>> someone investigate this?
> > Reading
> I have the impression that the current cygwin header behaviour
> is correct as siginfo_t is an extension POSIX.1-2008.

True, but I missed that struct sigaction (which is correctly guarded as 
POSIX.1-1990) uses siginfo_t.  This part needs to be guarded as 
POSIX.1b-1993 without breaking the struct, as is done in glibc.

> In theory "_GNU_SOURCE" should be defined by default

No, I'll fix this in the header shortly, along with updating libpng.


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