[RFA] use xsnprintf instead of snprintf.

[Joel Brobecker]

> gdb/gdbserver/ChangeLog:
> 
>         * utils.c (xsnprintf): Make non-static.
>         * server.h: Add xsnprintf declaration.
>         * linux-low.c, nto-low.c, target.c, thread-db.c, tracepoint.c:
>         replace calls to snprintf by calls to xsnprintf throughout.

Checked in :).

-- 
Joel