sh: Fix compilation with -DNO_HISTORY.

The LINENO code uses snprintf() and relied on "myhistedit.h" to pull in the
necessary <stdio.h>.

Compiling with -DNO_HISTORY disables all editing and history support and
allows linking without -ledit -ltermcap. This may be useful for embedded
systems.

MFC after:	2 weeks

bin/sh/parser.c

@@ -40,6 +40,7 @@ __FBSDID("$FreeBSD$");
 
 #include <stdlib.h>
 #include <unistd.h>
+#include <stdio.h>
 
 #include "shell.h"
 #include "parser.h"