diff --git a/lib/parser.c b/lib/parser.c
index 5bb837c..996f03d 100644
--- a/lib/parser.c
+++ b/lib/parser.c
@@ -632,11 +632,7 @@ iparse_sexp (char *s, size_t len, pcont_t *cc) {
  * cparse_sexp */
 pcont_t *eparse_sexp (char *str, size_t len, pcont_t *lc);
 
-#ifdef REGISTEROPTIMIZAITON
 #define REGISTER  register
-#else
-#define REGISTER
-#endif
 
 /**
  * Continuation based parser - the guts of the package.