telnet: Make function declarations C23 compatible.

[Collin Funk]

I made telnet use C23 compatible prototypes so now it can be built
using 'gcc -std=c23', for example.

With an exception for some Kerberos 4 stuff, which I cannot test. I
assume the plan is still to remove that as mentioned in TODO?

Also I think that ./configure  --with-shishi is broken, or maybe it is
because I have a local install? In any case, I could test telnet
commands including encryption by modifying my 'config.site'.

    $ ./telnet/telnet 
    telnet> encrypt type ?
    Usage: encrypt type <type> [input|output]
    Valid encryption types:
        DES_CFB64 (1)
        DES_OFB64 (2)

Collin

0001-telnet-Make-function-declarations-C23-compatible.patch
Description: Text Data