meson: better error for drm+gl deps

Helps people avoid GBM if they don't have it.

Signed-off-by: Pekka Paalanen <pq@iki.fi>

diff --git a/libweston/meson.build b/libweston/meson.build
index 81ae6ca5a5da3d0fbe818d9c4712b1a201aec408..492d59bfac4834c7adc88ad17fe343b33ed0659e 100644 (file)
--- a/libweston/meson.build
+++ b/libweston/meson.build
@@ -178,7 +178,10 @@ if get_option('backend-drm')
        ]
 
        if get_option('renderer-gl')
-               dep_gbm = dependency('gbm')
+               dep_gbm = dependency('gbm', required: false)
+               if not dep_gbm.found()
+                       error('drm-backend + gl-renderer requires gbm which was not found. Or, you can use \'-Dbackend-drm=false\' or \'-Drenderer-gl=false\'.')
+               endif
                if dep_gbm.version().version_compare('>= 17.1')
                        config_h.set('HAVE_GBM_MODIFIERS', '1')
                endif