tools: share getting program name from argv for all tools
diff --git a/tools/kmod.h b/tools/kmod.h
index 76a3426..7bf6c43 100644
--- a/tools/kmod.h
+++ b/tools/kmod.h
@@ -35,3 +35,6 @@
 extern const struct kmod_cmd kmod_cmd_compat_depmod;
 
 extern const struct kmod_cmd kmod_cmd_list;
+
+/* kmod.c */
+extern const char *binname;