meson: require shared glapi when using DRI based libGL

Just like we do in the autotools build.

Signed-off-by: Emil Velikov <emil.velikov@collabora.com>
Reviewed-by: Dylan Baker <dylan@pnwbakers.com>
Reviewed-by: Eric Engestrom <eric.engestrom@intel.com>
diff --git a/meson.build b/meson.build
index d4f460e..4aafba8 100644
--- a/meson.build
+++ b/meson.build
@@ -357,8 +357,12 @@
     if with_dri
       error('xlib conflicts with any dri driver')
     endif
-  elif with_glx == 'dri' and not with_dri
-    error('dri based GLX requires at least one DRI driver')
+  elif with_glx == 'dri'
+    if not with_dri
+      error('dri based GLX requires at least one DRI driver')
+    elif not with_shared_glapi
+      error('dri based GLX requires shared-glapi')
+    endif
   endif
 endif