rbmake: error: incomplete definition of type 'struct png_struct_def'

[ryandesign (Ryan Carsten Schmidt)]

​rbmake doesn't build:

pngimage.c:38:23: error: incomplete definition of type 'struct png_struct_def'
    if (setjmp(png_ptr->jmpbuf)) {
               ~~~~~~~^
/opt/local/include/png.h:439:16: note: forward declaration of 'struct png_struct_def'
typedef struct png_struct_def png_struct;
               ^
pngimage.c:104:23: error: incomplete definition of type 'struct png_struct_def'
    if (setjmp(png_ptr->jmpbuf)) {
               ~~~~~~~^
/opt/local/include/png.h:439:16: note: forward declaration of 'struct png_struct_def'
typedef struct png_struct_def png_struct;
               ^
2 errors generated.
make[1]: *** [pngimage.o] Error 1

It's not compatible with recent libpng. Usually this can be easily patched. Since this change in libpng was so long ago, somebody may already have a patch for this that we can find and use.

[ryandesign (Ryan Carsten Schmidt)]

In e8c2fe6ce2001f6b6f0bd7f57232ca86c17cb859/macports-ports (master):

rbmake: Fix build failures

Fix incompatibility with libpng 1.5 and later (use of the now-private
jmpbuf field).

Closes: #59554

Fix incompatibility with Xcode 12 and later (implicit declaration of
functions).