--- a/src/gallium/auxiliary/target-helpers/drm_helper_public.h
+++ b/src/gallium/auxiliary/target-helpers/drm_helper_public.h
@@ -4,10 +4,10 @@
 struct pipe_screen;
 struct pipe_screen_config;
 
-const char *iris_driconf_xml;
-const char *radeonsi_driconf_xml;
-const char *v3d_driconf_xml;
-const char *virgl_driconf_xml;
+extern const char *iris_driconf_xml;
+extern const char *radeonsi_driconf_xml;
+extern const char *v3d_driconf_xml;
+extern const char *virgl_driconf_xml;
 
 struct pipe_screen *
 pipe_i915_create_screen(int fd, const struct pipe_screen_config *config);