diff --git a/js/src/dtoa.c b/js/src/dtoa.c
index 5c4128ef5dc3..8d7352a635d7 100644
--- a/js/src/dtoa.c
+++ b/js/src/dtoa.c
@@ -2588,7 +2588,7 @@ nrv_alloc(CONST char *s, char **rve, int n)
  * when MULTIPLE_THREADS is not defined.
  */
 
- void
+ static void
 #ifdef KR_headers
 freedtoa(s) char *s;
 #else