libc: fix size check in select()

select() previously returned EINVAL only when nfds > FD_SETSIZE+1. The
right test is nfds > FD_SETSIZE, i.e., for nfds = FD_SETSIZE+1 this is also
an error.

Signed-off-by: Nadav Har'El <nyh@cloudius-systems.com>
Signed-off-by: Avi Kivity <avi@cloudius-systems.com>

core/select.cc

@@ -31,7 +31,7 @@ int select (int nfds,
     select_d("select(nfds=%d, readfds=0x%lx, writefds=0x%lx, exceptfds=0x%lx, timeout=0x%lx)",
         nfds, readfds, writefds, exceptfds, timeout);
 
-    if ((nfds < 0) || (nfds > FD_SETSIZE+1)) {
+    if ((nfds < 0) || (nfds > FD_SETSIZE)) {
         select_d("select() failed 1");
         errno = EINVAL;
         return -1;