[racket] Racket 5.3.4 doesn't build aginst libpng 1.6

When I tried libpng 1.6.2, it didn't work because PNG_LIBPNG_VER_STRING
includes a minor version number. I've pushed a repair for that problem,
and the patch should apply to v5.3.4:

https://github.com/plt/racket/commit/5629a6156a5720e51a277849f75b3135cb93664f

At Sat, 11 May 2013 09:32:49 -0600, Matthew Flatt wrote:
> The `racket/gui' library looks for "libpng15", "libpng12", and just
> "libpng", in that order.
> 
> So, maybe it should also look for "libpng16", which I'm guessing is
> the name of the libpng 1.6.2 library?
> 
> You can try adjusting
> 
>  collects/racket/draw/unsafe/png.rkt
> 
> to see if it works with "libpng16", or you could link "libpng.so" in
> the Racket "lib" directory to libpng16.so".
> 
> At Fri, 10 May 2013 18:23:01 -0400, Eric Bélanger wrote:
> > I'm trying to build racket 5.3.4 but I'm getting many similar errors:
> > png_structp->C: argument is not non-null `png_structp' pointer
> >   argument: #f
> > 
> > I found out that this only happens with libpng 1.6.2. It builds fine if I
> > use libpng 1.5.15.
> > 
> > Does anyone have a fix?
> > 
> > Thanks.
> > ____________________
> >   Racket Users list:
> >   http://lists.racket-lang.org/users
> 
> ____________________
>   Racket Users list:
>   http://lists.racket-lang.org/users