stdlib.c: remove duplicate libc_hidden_proto for strtoul/strtoul_l

Signed-off-by: Peter S. Mazinger <ps.m@gmx.net>

libc/stdlib/stdlib.c

@@ -375,7 +375,6 @@ strong_alias(strtoll,strtoq)
 /**********************************************************************/
 #if defined(L_strtoul) || defined(L_strtoul_l)
 
-libc_hidden_proto(__XL_NPP(strtoul))
 unsigned long __XL_NPP(strtoul)(const char * __restrict str,
 							char ** __restrict endptr, int base
 							__LOCALE_PARAM)