app-text/ghostscript-gpl: expose libgs.so ABI as subslot

Closes: https://bugs.gentoo.org/767421
Package-Manager: Portage-3.0.14, Repoman-3.0.2
Signed-off-by: Thomas Deutschmann <whissi@gentoo.org>

app-text/ghostscript-gpl/ghostscript-gpl-9.53.3-r5.ebuild

@@ -22,7 +22,7 @@ if [[ -n "${MY_PATCHSET}" ]] ; then
 fi
 
 LICENSE="AGPL-3 CPL-1.0"
-SLOT="0"
+SLOT="0/$(ver_cut 1-2)"
 KEYWORDS="~alpha amd64 arm arm64 hppa ~ia64 ~m68k ~mips ppc ppc64 ~riscv ~s390 sparc x86 ~amd64-linux ~x86-linux ~ppc-macos ~x64-macos ~sparc-solaris ~sparc64-solaris ~x64-solaris ~x86-solaris"
 IUSE="cups dbus gtk l10n_de static-libs unicode X"
 

app-text/ghostscript-gpl/metadata.xml

@@ -9,6 +9,9 @@
 		<email>printing@gentoo.org</email>
 		<name>Gentoo Printing Project</name>
 	</maintainer>
+	<slots>
+		<subslots>Reflect ABI of libgs.so.</subslots>
+	</slots>
 	<upstream>
 		<remote-id type="cpe">cpe:/a:artifex:gpl_ghostscript</remote-id>
 		<remote-id type="sourceforge">djvu</remote-id>