Fix platform selection, custom tools overrides, and user overrides of `use_mingw`#81700

Closed

shana wants to merge 3 commits intogodotengine:masterfrom shana:shana/fix-mingw-platform-tools

+183-128

Commits on Oct 12, 2023

Fix platform/target selection, let platforms override custom tools, obey overrides of use_mingw
shana
committed

Commits on Oct 13, 2023