Auto len calculation buffer overflow

[AGraber]

Regarding e1a9824, this "auto len calculation" by doing strlen to the final format string buffer is very prone to cause buffer overflows. The amx_SetString function won't be able to notice the array's real size and will just write out of bounds. The reason why the format required the size is to protect against this, not to arbitrarily limit the string output.

Why was this done in the first place?