[Buildroot] [PATCH v1] libsvg: fix undefined symbol png_set_gray_1_2_4_to_8

[Thomas Petazzoni <thomas.petazzoni@free-electrons.com>]

Dear Peter Seiderer,

On Thu,  5 Mar 2015 22:01:05 +0100, Peter Seiderer wrote:
> Fixes the following runtime error e.g. from df_texture:
> 
> (!) Direct/Interface: Unable to dlopen `/usr/lib/directfb-1.6-0/interfaces/IDirectFBImageProvider/libidirectfbimageprovider_svg.so'!
>     --> /usr/lib/libsvg.so.1: undefined symbol: png_set_gray_1_2_4_to_8
> 
> Signed-off-by: Peter Seiderer <ps.report@gmx.net>
> ---
>  ...-undefined-symbol-png_set_gray_1_2_4_to_8.patch | 32 ++++++++++++++++++++++
>  1 file changed, 32 insertions(+)
>  create mode 100644 package/libsvg/0002-Fix-undefined-symbol-png_set_gray_1_2_4_to_8.patch

Thanks, I've applied your patch. However:

 1/ libsvg is still severely broken. It uses symbols from libpng and
    libjpeg, but it doesn't link against those libraries. The output of
    'readelf -d' on libsvg says:

 0x00000001 (NEEDED)                     Shared library: [libxml2.so.2]
 0x00000001 (NEEDED)                     Shared library: [libc.so.0]
 0x0000000e (SONAME)                     Library soname: [libsvg.so.1]

    This means that if you try to compile an application with just
    '-lsvg', it doesn't build because the shared library doesn't
    express its dependency on other libraries. This is wrong.

    The configure.in script also doesn't check for the presence of
    libjpeg and libpng. Bad.

 2/ Isn't libsvg abandoned? Latest release in 2005. Same for
    libsvg-cairo. DirectFB is apparently the only remaining user of
    this library. Is the latest version of DirectFB still using
    libsvg-cairo ?

Best regards,

Thomas
-- 
Thomas Petazzoni, CTO, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com