gitlab-ci: build GLVND in meson-clang

Building GLVND in meson-main doesn't work because this disables
libEGL and it's needed for running shader-db.

Signed-off-by: Samuel Pitoiset <samuel.pitoiset@gmail.com>
Reviewed-by: Michel Dänzer <mdaenzer@redhat.com>

.gitlab-ci.yml

@@ -318,7 +318,6 @@ meson-swr-glvnd:
   variables:
     UNWIND: "true"
     DRI_LOADERS: >
-      -D glvnd=true
       -D egl=true
     GALLIUM_ST: >
       -D dri3=true
@@ -336,6 +335,8 @@ meson-clang:
   extends: .meson-build
   variables:
     UNWIND: "true"
+    DRI_LOADERS: >
+      -D glvnd=true
     DRI_DRIVERS: "auto"
     GALLIUM_DRIVERS: "auto"
     VULKAN_DRIVERS: intel,amd,freedreno