sysutils/gkrellm can't display PNG images since recent pkgsrc upgrade

[Marc Baudoin <babafou%babafou.eu.org@localhost>]

Hi,

I did a bunch of upgrades this week-end on a NetBSD/amd64 6.1.2
system and, since then, sysutils/gkrellm can't display PNG images
(which are used by themes).  When it starts, it prints a line
like this for each image it can't display:

  Cannot load file image: /home/foo/.gkrellm2/themes/<themename>/file.png

sysutils/gkrellm has not changed recently but graphics/png did
(and it got upgraded just before the problem appeared).
I wonder if this is a problem with the PNG library because
sysutils/gkrellm seams to be the only application impacted on my
system.

Does anybody has the same problem?