[gimp/wip/Jehan/ninja-test] build: xvfb-run call from meson fails.

[Jehan <jehanp src gnome org>]

commit 29737e326f74a69168080f49e008607b21144868
Author: Jehan <jehan girinstud io>
Date:   Sun Nov 14 18:34:05 2021 +0100

    build: xvfb-run call from meson fails.
    
    Note that I first thought to use the full option name (`--auto-display`)
    but I just got the same error again. It seems xvfb-run from Debian
    bookworm just doesn't have this option, and only the older option
    --auto-servernum (which is said to be deprecated in favor of
    --auto-display in Fedora's xvfb-run for instance, but apparently not on
    Debian). At least this works on all distributions (or so it would seem).
    
    Fixes:
    
    > xvfb-run: invalid option -- 'd'

 build/meson/run_test_env.sh | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/build/meson/run_test_env.sh b/build/meson/run_test_env.sh
index 19cb191052..19a1529d5a 100644
--- a/build/meson/run_test_env.sh
+++ b/build/meson/run_test_env.sh
@@ -11,7 +11,7 @@ if [ -n "${UI_TEST}" ]; then
   # Also use dbus-run-session to make sure parallel tests aren't failing
   # as they simultaneously try to own the "org.gimp.GIMP.UI" D-Bus name
 
-  xvfb-run -d --server-args="-screen 0 1280x1024x24" \
+  xvfb-run --auto-servernum --server-args="-screen 0 1280x1024x24" \
     dbus-run-session -- "$@"
 
 else