Upstream bug: https://bugs.ghostscript.com/show_bug.cgi?id=697457
A new release containing this fix is expected in march; until then,
apply patch from upstream. Note that there have been essentially no
changes between 0.13 and this patch.
The most recent version on the sourceforge page is 0.11 which is quite
old; the official upstream site has 0.13; judging by the commit delta,
there've been quite a few bug fixes etc since 0.11.
