Improvements in mint.cnf (xaaes.cnf) parsing

[mikrosk]

I can think of two major improvements:

• allow usage of relative paths i.e. if mint.cnf is located in c:\mint\mint-123\mint.cnf it wouldn't complain about executing binaries relative to that (or $SYSDIR -- perhaps easier) path
• allow usage of either real env variables or some faked ones -- $SYSDIR and $MCHDIR are obvious candidates (this reminds me introduction of $MCHDIR as an env variable...)

With at least one of the changes one could use universal configuration files across different builds, esp. true for INIT/GEM and xaloader.prg path.

[paulwratt]

this is definitely a candidate for a v1.20 release.

note that ENV parsing should be on per line basis, not per file, as both MiNT and XaAES define ENV variables through out there configs.