Fix "Mixing of declarations with code causes errors in GCC v2.95.3" -- #5723

This patch moves a single declaration line in ido2db.c to get it away
from the code surrounding it.  This is a portability change only.

Note that the C90 standard technically prohibits intermixing of
declarations and code, but GCC, especially at lower levels, tends
to ignore that.

Fixes #5723
idoutils: Allow agent_version to store more than 16 chars.

Fixes #5731