Flip the soft-default to a hard "missing package clause" error symmetrically in
both stages (cmd/wcc/parse.c + lib/ww/syntax/parse.ww): the first real decl of a
primary section with empty pathmod/resetmod and no seen clause is now rejected.
Closes the documented soft-default divergence (the 63-wrapper carve-out).
The gate flip can't be split from the migration it breaks, so this is one atomic
commit: ~80 test/wcc wrappers gain `package main;` via a shared wwtestpkg.h
helper, 6 data fixtures plus 17 asm-grep assertions update for the bare->main.<leaf>
root-helper mangle shift, and rt/ declares `package rt;` with @symbol pinning the
bare rt_ensure/rt_malloc linker names.
Root mangling narrows: the executable entry `main` stays bare (existing
carve-out), but root helper symbols become main.X. The #84 cluster is rewritten
to assert main.run distinct from aa.run/test.run; its cgen fix and bare machinery
are retained — still load-bearing for package-less module-reset deps. New
table-driven test 782_strict_package.c (6 rows, both stages).
Retiring //ww:module-reset is deferred to #24b: it is load-bearing (clears the
.wwi pathmod so the body's package clause asserts), not a vestige; fusing its
removal here would be a silent mismatch.
All byte-id gates green; full make test reports "all 335 tests passed".
libdirs, lflags and inputs were fixed 64-slot arrays written with no
bound check; the 65th -L/-l flag (or input) wrote past the allocation
-> heap corruption. Size all three by argc instead, the true upper
bound since each argv slot yields at most one entry, mirroring cstage
cmd/w6l/main.c:63-67 (calloc(argc, ...)). Drop the now-dead maxinputs
"too many inputs" cap -- cstage has none, and argc-sizing makes it
unreachable.
Regenerates the w6l combined.ww. Table-driven 632 test reaches a lib
only via the Nth -L (N in {1,64,65,100,128}, both stages); pre-fix the
nflags=65 row fails (slot one past the 64-array).
