Comment # 6 on bug 953149 from Dominique Leuenberger

[   89s] + IFS=.
[   89s] + read GS_MAJ GS_MIN
[   89s] ++ rpm -q --qf '%{version}' ghostscript-devel
[   89s] + IFS='        
[   89s] '

so 13.2 does not like to read into two variables; that's buuuh!

GS unfortunately does not offer anything useful in the headers to identify
which version you're building against - they only have a variant to get the
version at runtime... so I needed this crazy trickery to find out when to apply
the patch.

Comparing version numbers is always a pain; I can as well resort to something
like:

BuildRequires: zypper

%prep
if [ zypper vcmp $(rpm -q --qf '%%{version}' ghostscript-devel) 9.18 | grep -e
"\(newer\|matches\)" ]; then
%patch0
fi

That should also work on 13.2 then.