Added temporarily shutdown() function for static openssl.
Added some dummy implementations for some clib functions.

The static openssl would need them. Note we need a sscanf() implementation
before it works.
Decrease size of local buf by 100 and protect against buffer overruns.
Added digit shortcut for the single account check menu entries.

The first account can be checked via Amiga + 1, the second via Amiga + 2,
and so on.