Thirty-one cases only ever emitted C and never built it -- m5 owned/defer, and
every ok* acceptance fixture in m6 and m7. They asserted that fec produced a
file, not that the file was a program, so a malformed emission sat unnoticed.
Compile each one with wcl386 -c. Fixtures without a main cannot be run, so this
is the floor for them; it is a conformance check on the backend's output, not an
assertion about C, so a future backend swaps the command rather than the intent.
It found two defects in the M6 emitter immediately, both predating M7:
&s[0] took the address of an rvalue. Borrowing went through emit_expr, which
lowers an index to the bounds-checking accessor, so `&s[0]` became
`&fe_idx_slice_type_2(s, 0)`. emit_lvalue spells the same element as `s.p[0]`.
The M7 emitter already did this correctly; only the M6 path was wrong.
line.trim() was never lowered. SPEC lists trim among the built-in alias methods
on str and the checker accepts it, but no emitter case existed, so it emitted
`fe_l_line_0.trim()` -- a member access on a slice struct. Emit the helper, and
only for programs that actually trim.
Also set core=dynamic and cycles=max. core=auto uses the interpreter in real
mode, which is where the 16-bit compiler build spends its time; nothing here is
timing sensitive. m6 drops from 31s to 17s. Raise the DOSBox timeout to match a
whole-suite run, which now pays a process spawn per compile check.
Verified: --only m6, 57 passed.