nx_ccgate_lib.nx

nx_ccgate_lib.nx -- THE ONE compiler-gate driver: fork/exec a toolchain compiler on a fixture with an optional mode flag, assemble with nxasm, run the fixture by phase, read back stderr captures. Extracted 2026-08-23 from the LN3 gate (nx_boundscheck_gate, whose helpers it reproduces verbatim in behaviour) the day a SECOND and THIRD compiler-mode gate needed them (nx_chkarith_gate for LN1, nx_opt_eqsat_wire_gate for LN8): three private copies of one driver is the duplicate-ruler defect, and a fix to the driver (e.g. the noexec-/tmp placement lesson) must land once. CONVENTIONS CARRIED (all measured in the LN3 gate's record): * data captures (.s, .err) live in /tmp/<gate>/; every ELF THAT MUST RUN lives under _build/ -- the NAS mounts /tmp noexec (execve EACCES 126), so a runnable staged in /tmp passes its compile teeth and fails every run tooth with no diagnostic; * per-run-unique names carry the gate's pid (two concurrent runs racing one rename source is a documented incident class); * ccg_build returns phase codes (0 ok, 1 compile-fail, 2 asm-fail, 3 rename-fail) that the gate PRINTS before its teeth -- a FAIL-only tooth cannot say why; * ccg_anchor_root chdirs into buildroot when the tools-API exec lane starts the gate in the serving root (whose _offc carries no compiler); the laptop lane misses the probe and stays put. license_tier: ORIGINAL No hw writes (Rule 26).