Re: [Qemu-devel] Fix build break during configuration on musl-libc based Linux systems.

[Peter Maydell]

On 17 February 2017 at 11:20, Paolo Bonzini <address@hidden> wrote:
>
>
> On 17/02/2017 11:18, Peter Maydell wrote:
>> Defining _XOPEN_SOURCE is easy enough, and I think we should
>> do it unconditionally. We should check what effect this has
>> on the BSD hosts though I guess. (You could argue that we
>> should be defining _XOPEN_SOURCE anyway for the benefit of
>> the non-glibc BSD/Solaris/etc platforms.)
>
> Sounds good, then I think we should define it to 700 just like glibc does.

Unfortunately this idea turns out to break OSX compiles,
because on OSX saying _XOPEN_SOURCE=anything disables
all the non-X/Open APIs (which you get by default, and
some of which like mkdtemp we use).

Looking at the manpage for Solaris
https://www.freebsd.org/cgi/man.cgi?query=standards&apropos=0&sektion=0&manpath=SunOS+5.8&format=html
it seems to also go with "_XOPEN_SOURCE means *only* those
functions", though its mechanism for saying "and the other
stuff too" is different (define __EXTENSION__).

So perhaps we'd better stick with "only define this for
Linux hosts".

thanks
-- PMM