Bugzilla Bug 136346

Emerging net-print/cups-1.1.23-r7 while media-libs/libpng-1.2.10 is installed
results in:

Linking imagetops...
Linking rastertoepson...
Linking rastertohp...
../filter/libcupsimage.so: undefined reference to `png_read_destroy'
collect2: ld gab 1 als Ende-Status zur

Emerging net-print/cups-1.1.23-r7 while media-libs/libpng-1.2.10 is installed
results in:

Linking imagetops...
Linking rastertoepson...
Linking rastertohp...
../filter/libcupsimage.so: undefined reference to `png_read_destroy'
collect2: ld gab 1 als Ende-Status zurück
make[1]: *** [rastertoepson] Fehler 1
make[1]: *** Warte auf noch nicht beendete Prozesse...
../filter/libcupsimage.so: undefined reference to `png_read_destroy'
collect2: ld gab 1 als Ende-Status zurück
make[1]: *** [imagetops] Fehler 1
../filter/libcupsimage.so: undefined reference to `png_read_destroy'
collect2: ld gab 1 als Ende-Status zurück
make[1]: *** [rastertohp] Fehler 1
../filter/libcupsimage.so: Error reference to `png_read_destroy'
collect2: ld gab 1 als Ende-Status zurück
make[1]: *** [rastertodymo] Fehler 1
make: *** [all] Fehler 1

(There's no png_read_destory in /usr/include/png.h in libpng-1.2.8-r1 there
was)

Downgrading to libpng-1.2.8-r1 works for me.

you can try upgrading to cups-1.2.1 :)
I think it is stable enough, but we still need to write an upgrade guide.

got an explanation here:
http://mail-index.netbsd.org/pkgsrc-users/2006/04/17/0000.html

box ~ # cd /usr/lib
box lib # ls -l libpng*
lrwxrwxrwx 1 root root     10 Jun 11 21:46 libpng.a -> libpng12.a
lrwxrwxrwx 1 root root     11 Jun 11 21:46 libpng.la -> libpng12.la
lrwxrwxrwx 1 root root     11 Jun 11 21:46 libpng.so -> libpng12.so
lrwxrwxrwx 1 root root     16 Jun 11 21:46 libpng.so.3 -> libpng.so.3.10.0
-rwxr-xr-x 1 root root 152012 Jun 11 21:46 libpng.so.3.10.0
-rw-r--r-- 1 root root 178002 Jun 11 21:46 libpng12.a
-rw-r--r-- 1 root root    804 Jun 11 21:46 libpng12.la
lrwxrwxrwx 1 root root     18 Jun 11 21:46 libpng12.so -> libpng12.so.0.10.0
lrwxrwxrwx 1 root root     18 Jun 11 21:46 libpng12.so.0 -> libpng12.so.0.10.0
-rwxr-xr-x 1 root root 142656 Jun 11 21:46 libpng12.so.0.10.0
box lib # rm libpng.so
box lib # ln -s libpng.so.3.10.0 libpng.so

manually recreating the /usr/lib/libpng.so symlink worked for me.

Compiling the Gimp compiles with the same error, see bug 136346
The solution given in comment #2 does not solve it there. 
So I guess a better solution needs to be found. 

Ah, great... confirmed the gimp problem. I found gimp linking against
libpng12.so and thought it was maybe that library, but... there was <a
href="http://sourceforge.net/tracker/index.php?func=detail&aid=1474685&group_id=5624&atid=105624">this
bug</a> for libpng, now it seems both gimp and cups should be patched to no
longer use those functions.

I have done the following:

- unmasked cups-1.2 which works with the new libpng
- made the depend <media-libs/libpng-1.2.10 in cups-1.1 so that you can
downgrade if needed :)

*** Bug 136857 has been marked as a duplicate of this bug. ***

reopen. kojiro will provide a patch. We would appreciate some testing :)

Created an attachment (id=90787) [details]
cups-1.1.23-image-png.patch

Very simply replaces the deprecated 
  png_read_destroy(pp, info, NULL);
with the new
  png_destroy_read_struct(&pp, &info, NULL);

Created an attachment (id=90788) [details]
cups-1.1.23-r8.ebuild

adds a line to epatch cups-1.1.23-image-png.patch

Created an attachment (id=90790) [details]
cups-1.1.23-r8.ebuild

Improved ebuild with proper >=media-libs/libpng-1.2.10 dependency

ok, I have committed it to the current ebuild. No revision bump, because it is
just a buildfix

Uhh - the patch changes the source, isn't cups going to have to be rebuilt in
order to make sure it works with the new libpng??  ..and won't this only happen
if we do a revision bump?

thanks ian, I added a revision bump now :)