From bc14fa1b1cceb7c064a7129132c2290ff40b9b35 Mon Sep 17 00:00:00 2001
From: Jan Wielemaker <jan@swi-prolog.org>
Date: Wed, 23 Oct 2024 17:08:47 +0200
Subject: [PATCH] BUILD: Make sure to clear ``DISPLAY`` when running xpce steps

While the build works without a DISPLAY variable, an invalid variable
causes the build to fail.
---
 cmake/QLF.cmake | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/cmake/QLF.cmake b/cmake/QLF.cmake
index 187f53a64a..6878fc20a9 100644
--- a/cmake/QLF.cmake
+++ b/cmake/QLF.cmake
@@ -58,7 +58,8 @@ function(add_swipl_target name)
   add_custom_command(
       OUTPUT ${my_OUTPUT}
       BYPRODUCTS ${my_BYPRODUCTS}
-      COMMAND ${PROG_SWIPL} ${options} ${my_OPTIONS}
+      COMMAND ${CMAKE_COMMAND} -E env --unset=DISPLAY
+	      ${PROG_SWIPL} ${options} ${my_OPTIONS}
       COMMENT "${my_COMMENT}"
       DEPENDS core prolog_home
               ${SWIPL_COMMAND_DEPENDS} "${my_DEPENDS}"