Improve compatibility with some crappy Telnet server (e.g. in C64 BBSes):

Send CR/NUL for <Enter> rather than CR/LF. Although the Telnet spec (RFC854)
requires that either combination be accepted as a single "new line" character,
some Telnet servers treat CR and LF as separate input characters and do weird
things (e.g. treat the LF as a second <Enter> key or <^J> or invalid input).
If we ever come across a Telnet server that does something weird with CR/NUL
(and works better receiving CRLF) then perhaps we'll need a configuration
option. Hopefully not. Of course, in binary mode, none of this applies.

src/syncterm/telnet_io.c

@@ -281,7 +281,7 @@ BYTE* telnet_expand(BYTE* inbuf, size_t inlen, BYTE* outbuf, size_t *newlen)
 		outbuf[outlen++]=inbuf[i];
 		if(telnet_local_option[TELNET_BINARY_TX]!=TELNET_DO) {
 			if(inbuf[i]=='\r')
-				outbuf[outlen++]='\n';
+				outbuf[outlen++]=0;	// Some Telnet servers when receiving CRLF as an "Enter" character
 		}
 	}
     *newlen=outlen;