diff --git a/ext/Makefile.am b/ext/Makefile.am
index 7b70bc45b6..bd24b63787 100644
--- a/ext/Makefile.am
+++ b/ext/Makefile.am
@@ -152,7 +152,6 @@ endif
 
 if USE_SDL
 SDL_DIR=sdl
-SDL_DIR=
 else
 SDL_DIR=
 endif