SDL_image 1.2.12 redraw issues

[andydvsn]

SDL_image 1.2.12 caused major redraw errors where bitmaps were not displayed and text was redrawn over old text. Need to work out where that bug crept in if a later revision of SDL_image becomes required.

[andydvsn]

Earlier versions past 1.2.7 also do not compile, failing like this:

In file included from /usr/include/libpng16/pngconf.h:50:0,
                 from /usr/include/libpng16/png.h:366,
                 from IMG_png.c:70:
IMG_png.c: In function 'IMG_LoadPNG_RW':
IMG_png.c:348:21: error: dereferencing pointer to incomplete type 'png_struct {aka struct png_struct_def}'
  if ( setjmp(png_ptr->jmpbuf) ) {
                     ^
IMG_png.c:417:21: error: dereferencing pointer to incomplete type 'png_info {aka struct png_info_def}'
    Amask = (info_ptr->channels == 4) ? 0xFF000000 : 0;
                     ^~
Makefile:438: recipe for target 'IMG_png.lo' failed
make[1]: *** [IMG_png.lo] Error 1
make[1]: Leaving directory '/home/andy/Development/squeezeplay/src/SDL_image-1.2.8'
Makefile.linux:114: recipe for target 'sdl-image' failed
make: *** [sdl-image] Error 2