Toolchain choice notes

FreeBASIC can use different external C/C++ and linker toolchains depending on the target. The current build system tries to keep that selection centralized instead of scattering compiler names through individual rules.

Where selection happens

Toolchain selection is mainly handled by the platform, CPU, compiler-config, toolchain-flags, host-tools, and OS flag modules under `mk/`. If a target is choosing the wrong compiler or linker, fix the target identity or toolchain module before changing unrelated compile rules.

General guidance

Use the distro or MSYS2 package scripts when building release artifacts. They install or locate the expected compiler family for that host. Use direct make variables for focused development or for bringing up a new target, then fold the working choices back into the proper `mk/` module or build script.