env: make import/export optional

Signed-off-by: Mike Frysinger <vapier@gentoo.org>
diff --git a/include/config_cmd_defaults.h b/include/config_cmd_defaults.h
index 9283daa..6adebdb 100644
--- a/include/config_cmd_defaults.h
+++ b/include/config_cmd_defaults.h
@@ -10,5 +10,7 @@
 #define _CONFIG_CMD_DEFAULTS_H_
 
 #define CONFIG_CMD_BOOTM 1
+#define CONFIG_CMD_EXPORTENV 1
+#define CONFIG_CMD_IMPORTENV 1
 
 #endif