From 1a3aa5c32117e94d8838c8ec85a68e8ae83898c5 Mon Sep 17 00:00:00 2001
From: Simon Warta <simon@kullo.net>
Date: Sat, 6 Apr 2019 15:05:50 +0200
Subject: [PATCH] cmake: don't run SORT on empty list

In case of an empty list, SORTing leads to the cmake error "list
sub-command SORT requires list to be present."

Closes https://github.com/curl/curl/pull/3736
---
 CMakeLists.txt | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index edb1cec21..6f513c2bc 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -1239,7 +1239,9 @@ _add_if("SCP"           USE_LIBSSH2)
 _add_if("SFTP"          USE_LIBSSH2)
 _add_if("RTSP"          NOT CURL_DISABLE_RTSP)
 _add_if("RTMP"          USE_LIBRTMP)
-list(SORT _items)
+if(_items)
+  list(SORT _items)
+endif()
 string(REPLACE ";" " " SUPPORT_PROTOCOLS "${_items}")
 message(STATUS "Enabled protocols: ${SUPPORT_PROTOCOLS}")