The linker-script stamp now records the sha256 of the written content, so
an externally edited or truncated cached script regenerates instead of
passing a SECTIONS substring probe, and a non-UTF-8 cached script is
overwritten by the regeneration instead of aborting it. The cached
preprocessor diagnostic re-emit no longer swallows its own read failure.
board_build.f_cpu is validated (digits with an optional L) before landing
unquoted on the compile line, _pio_option rejects empty and blank values
instead of silently reverting to the default, and user MMU define bodies
re-quote through shell_token like every other user token. The plain-form
linker denylist is a named constant the _project_flags docstring points
at, so the two cannot drift.
J. Nick Koston
dc1bbac385