erc-sh-archive: add checking for 7zr and 7zz

bin/erc-sh-archive

@@ -32,7 +32,14 @@ set_backend()
 	if [ -n "$use_7z" ] || ! have_patool ; then
 		# TODO: try install patool and p7zip
 		is_command 7za && HAVE_7Z='7za'
-		#is_command 7z && HAVE_7Z='7z'
+		if ! is_command $HAVE_7Z ; then
+			# 7-zip
+			is_command 7zz && HAVE_7Z='7zz'
+		fi
+		if ! is_command $HAVE_7Z ; then
+			# reduced p7-zip
+			is_command 7zr && HAVE_7Z='7zr'
+		fi
 		is_command $HAVE_7Z || fatal "Could not find any patool or 7-zip backend. Please install p7zip package and retry."
 	fi
 	[ -z "$force" ] || HAVE_7Z="$HAVE_7Z -y"