diff --git a/premake/celt.lua b/premake/celt.lua
index 11adc67..941b65c 100644
--- a/premake/celt.lua
+++ b/premake/celt.lua
@@ -9,7 +9,9 @@ group "external"
 
         defines
         {
-            "restrict="
+            "restrict=",
+            "CUSTOM_MODES",
+            "CUSTOM_MODES_ONLY"
         }
         includedirs
         {