[Pixman] Pixman on iOS

[cu]

I am starting to look (very carefully) into building pixman and, one day
may be, cairo on iphone/ipad/iOS.

So far I've got to the point where I can configure and build pixman for
a single arm architecture. So far so good.
However, I seem to be unable to enable NEON optimizations. Presumably,
iPhone/iPad armv7 does have those.

I wonder if the issue is specific set of compiler directives used to
access NEON operations? Any help or insight would be appreciated.

As an aside, pixman configure script does not recognize that iOS
supports pthreads and accordingly omits HAVE_PTHREAD_SETSPECIFIC from
configuration. This is easily repaired "by hand" but configure probably
needs to be updated.

Thanks all!
--
Mike