maint/build ~ (Makefile.win) update (v2023.10.09); fixes and refine

- fix 'define.h' update logic
- multiple other small fixes
- improved robustness of shell environment variable handling
- feedback display improvements
- improved separation of concerns for shell command functions
- revised function names for better clarity
- DRY improvements
- commentary polish
- improve correspondence between Makefile types (ie, CC vs Go)