erc-sh-archive: prefer 7zz (official 7-Zip) over deprecated p7zip

bin/erc-sh-archive

@@ -26,7 +26,8 @@ have_patool()
 
 set_backend()
 {
-	HAVE_7Z='7z'
+	# prefer 7zz (official 7-Zip) over 7z (p7zip, deprecated since 2021)
+	HAVE_7Z='7zz'
 
 	[ "$ERC_BACKEND" = "patool" ] && use_patool=1
 	[ "$ERC_BACKEND" = "7z" ] && use_7z=1
@@ -36,8 +37,8 @@ set_backend()
 	if [ -n "$use_7z" ] || ! have_patool ; then
 		# TODO: try install patool and p7zip
 		if ! is_command $HAVE_7Z ; then
-			# 7-zip
-			is_command 7zz && HAVE_7Z='7zz'
+			# p7zip (deprecated, does not preserve permissions)
+			is_command 7z && HAVE_7Z='7z'
 		fi
 		if ! is_command $HAVE_7Z ; then
 			# reduced p7-zip