Bootstrapping FreeBASIC

FreeBASIC can rebuild itself, but the path depends on what compiler and bootstrap sources are already available. The current make system keeps bootstrap logic in `mk/bootstrap/` and exposes named targets for the common states.

Common bootstrap targets

    make prereqs-fbc
    make bootstrap-minimal
    make bootstrap-seed-peer
    make bootstrap-emit
    make bootstrap-dist-target

The right target depends on whether the host already has a usable `fbc`, a system package compiler, or target-specific generated bootstrap sources.

How to debug bootstrap problems

Start with `make print-config` and `make prereqs-fbc`. Bootstrap failures are usually easier to understand after confirming the selected host, target, bootstrap compiler, backend, binary names, and output directories.

If a new platform cannot even run a previous FreeBASIC compiler, generate or stage bootstrap sources from a platform that can. Avoid changing parser or code generation behavior just to make a bootstrap step pass until the failure has been traced to the real portability problem.