Bug 451187 JS causes a crash in nspr [@ Bfree ]

freedtoa should be marked as static as the data type returned by these implementations does not need to be freed with it
r=crowder

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