thoughts for todo and other docs

[rakslice]

(TODOs here are in addition to the ones in https://github.com/rakslice/aix_ps2_gcc_kit/blob/main/TODO)

• I've tested running through this scripted build but I haven't actually tested the resulting compiler on the aix machine; this kit is basically the result of an attempt to rework how i originally built a working gcc 2.7.2.3 via cross compiling, based on taking apart the artifacts i had left sitting around (on, inbound to, and outbound from) the rh5 vm i originally built it on. At this point if it doesn't work yet it should at least still be a good starting point for getting around some of the rough parts because I did get a working compiler with the same approach originally.
• I need to double check that this scripted build works with the original headers as-is... I've been testing using the headers dump that I originally used as the starting point for further changes to get a set I used with the working cross compiler I built manually before, but they underwent an unknown amount of potential hacking up on the AIX box itself before being exported as I tried to cross-compile things on-box. Basically I need to go through the process of installing a fresh aix ps/2 vm with the dev disk sets w/ headers and exporting them to test with (and compare against the import I am using)
• Make a note about leaix (https://github.com/rakslice/leaix/) in the README -- since my interest in maybe building an ethernet driver for vbox is what made me power through getting gcc cross-compiled the first time.

[rakslice]

Okay, so I compared my old input headers against those from a fresh install; there were a number of differences due to the old input headers being older versions (the relevant PTF0024 changes for the particular product sets they were from must not have been applied), but there were no local edits that I noticed

[rakslice]

• I've now tested with the resulting compiler and it's about where my previous manual build was at.