unsigned char casts for is*, casts for socket functi, add headers

git-svn-id: svn://svn.h5l.se/heimdal/trunk/heimdal@10646 ec53bebd-3082-4978-b11e-865c3cabbd6b

appl/telnet/telnetd/utility.c

@@ -1152,7 +1152,7 @@ printdata(char *tag, char *ptr, int cnt)
 	output_data("%s: ", tag);
 	for (i = 0; i < 20 && cnt; i++) {
 	    output_data("%02x", *ptr);
-	    if (isprint(*ptr)) {
+	    if (isprint((unsigned char)*ptr)) {
 		xbuf[i] = *ptr;
 	    } else {
 		xbuf[i] = '.';