exact-image: error: invalid use of incomplete type 'struct png_info_def'

[paoloyx@…]

MacOsX 10.8 (MountainLion), Xcode4.3, Trying to install exact-image 0.8.4_1. As building with clang gives an error, according to building using another compiler, i'm trying to build using llvm-gcc-4.2. But i receive the following error:

--->  Computing dependencies for exact-image
--->  Fetching archive for exact-image
--->  Attempting to fetch exact-image-0.8.4_1.darwin_12.x86_64.tbz2 from http://lil.fr.packages.macports.org/exact-image
--->  Attempting to fetch exact-image-0.8.4_1.darwin_12.x86_64.tbz2 from http://mse.uk.packages.macports.org/sites/packages.macports.org/exact-image
--->  Attempting to fetch exact-image-0.8.4_1.darwin_12.x86_64.tbz2 from http://packages.macports.org/exact-image
--->  Fetching distfiles for exact-image
--->  Verifying checksum(s) for exact-image
--->  Extracting exact-image
--->  Applying patches to exact-image
--->  Configuring exact-image
--->  Building exact-image
Error: org.macports.build for port exact-image returned: command execution failed
Please see the log file for port exact-image for details:
    /opt/local/var/macports/logs/_opt_local_var_macports_sources_rsync.macports.org_release_tarballs_ports_graphics_exact-image/exact-image/main.log
To report a bug, follow the instructions in the guide:
    http://guide.macports.org/#project.tickets
Error: Processing of port exact-image failedfailed

Then i've tried to build using apple-gcc-4.2, but i receive the same error as before.

[paoloyx@…]

Build log using llvm-gcc-4.2

[paoloyx@…]

Build log using apple-gcc-4.2

[ryandesign (Ryan Carsten Schmidt)]

Both logs show the error:

error: invalid use of incomplete type 'struct png_info_def'

which indicates an incompatibility with libpng 1.5. The first thing we should try is to update the port to a newer version.

[ryandesign (Ryan Carsten Schmidt)]

The latest version still has the libpng 1.5 incompatibility so we'll have to locate a patch or write one ourselves.

[ryandesign (Ryan Carsten Schmidt)]

Here's a patch: ​https://gist.github.com/3004353

[ryandesign (Ryan Carsten Schmidt)]

We already had a patch for libpng 1.4 compatibility; I added the lines needed for libpng 1.5 compatibility in r99117.

[paoloyx@…]

Ok, just to confirm that the patch did the trick. Thanks a lot.