From 7c7323668d2d10971266d6b0b64501e9fdb7af86 Mon Sep 17 00:00:00 2001
From: Alexander Koeppe <format_c@online.de>
Date: Fri, 19 Apr 2019 08:34:38 +0200
Subject: [PATCH] Remove Cmake list duplicates only if list exists

---
 cmake/Modules/EttercapLibCheck.cmake | 14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

diff --git a/cmake/Modules/EttercapLibCheck.cmake b/cmake/Modules/EttercapLibCheck.cmake
index 1c048c860..d0873a54c 100644
--- a/cmake/Modules/EttercapLibCheck.cmake
+++ b/cmake/Modules/EttercapLibCheck.cmake
@@ -332,5 +332,15 @@ if(ENABLE_LUA)
 endif()
 
 # Clean up
-list(REMOVE_DUPLICATES EC_INCLUDE)
-list(REMOVE_DUPLICATES EC_UI_INCLUDE)
+if(EC_INCLUDE)
+  list(REMOVE_DUPLICATES EC_INCLUDE)
+endif()
+if(EC_UI_INCLUDE)
+  list(REMOVE_DUPLICATES EC_UI_INCLUDE)
+endif()
+if(EC_LIBS)
+  list(REMOVE_DUPLICATES EC_LIBS)
+endif()
+if(EC_UI_LIBS)
+  list(REMOVE_DUPLICATES EC_UI_LIBS)
+endif()