diff --git a/iconv/iconvconfig.c b/iconv/iconvconfig.c
index 05b3c9d9a7..3daf65f858 100644
--- a/iconv/iconvconfig.c
+++ b/iconv/iconvconfig.c
@@ -202,6 +202,8 @@ static struct
 			       MinT, MaxT)
 #include <gconv_builtin.h>
   };
+#undef BUILTIN_ALIAS
+#undef BUILTIN_TRANSFORMATION
 #define nbuiltin_alias (sizeof (builtin_alias) / sizeof (builtin_alias[0]))
 
 static struct