Derelict / SDL error

[Paul via Digitalmars-d-learn]

On Wednesday, 10 December 2014 at 09:07:56 UTC, ketmar via 
Digitalmars-d-learn wrote:
> do you have the corresponding libraries installed? SDL_Image 
> uses
> libpng and libjpeg for decoding images, so if you don't have 
> those
> installed (with corresponding -dev if your system needs that) 
> you will
> not be able to load images in those formats.
>
> also please note that libpng has two incompatible versions, so
> double-check README for SDL_Image.

On Wednesday, 10 December 2014 at 09:07:56 UTC, ketmar via 
Digitalmars-d-learn wrote:
> do you have the corresponding libraries installed? SDL_Image 
> uses
> libpng and libjpeg for decoding images, so if you don't have 
> those
> installed (with corresponding -dev if your system needs that) 
> you will
> not be able to load images in those formats.
>
> also please note that libpng has two incompatible versions, so
> double-check README for SDL_Image.

The readme for SDL_image doesn't say anything about incompatible 
versions of libpng - I have version 1.2.46 installed along with 
the dev files. It also says zlib is required and those are also 
installed.

On the project page[1] is lists libpng 1.5.7 as being used for 
the pre-built binaries (presumably for Win) although the link it 
provides is dead.

libpng 1.5.2 is the nearest version on that project page[2]. I 
built that then rebuilt SDL_image. dub --force now gives me:

IMG_Load error: Failed loading png_set_longjmp_fn: 
/lib/i386-linux-gnu/libpng12.so.0: undefined symbol: 
_png_set_longjmp_fn

Which looks like it is still referring to the old version of 
libpng.

I downloaded the source for the latest version of libpng but 
there is no simple install procedure - the configuration required 
is beyond my level of knowledge.

This thread has degenerated into a discussion of the set up of my 
OS which is miles off topic and should probably be abandoned. 
Thanks for trying all the same.

[1]https://www.libsdl.org/projects/SDL_image/
[2]http://www.libpng.org/pub/png/libpng.html