parsefile's recovery fallback chewed an unrecognized top-level
construct to the next ';' without emitting an error or bumping p.errs,
so a typo'd keyword / stray token silently vanished from the AST and
the build succeeded rc=0 with the declared work gone — no link error
catches a dropped @test or unreferenced exported fn. The C twin
(parse.c:1395-1400) errorf+p->errs++ and rejects. Emit errmsg in the
fallback arm; wwstage now rejects in lockstep with cstage.
lib/ww embeds into the w6c/wwdump combined.ww snapshots; both regen'd.
989_unknowndecl_reject pins the reject-matrix on both driver twins.