nxrun.nx

nxrun.nx -- sovereign replacement for bench/run.sh. Compiles each benchmark's C baseline with gcc, times its execution, compiles the NishiLang variant with nxc2, times its execution, prints a tab-separated comparison. Uses the process-control syscalls (sys_fork / sys_execve / sys_wait4) shipped earlier in this session. Removes bash from one more pathway in the nishi-core build chain. Pair with f6_gate.nx (F6 reproducibility gate) to cover every shell script currently in the repo except the gcc build (Makefile, driven by host `make`). Four invariants: NR1 Same gcc / nxc2 invocation as run.sh; numbers comparable across the bash-driven and .nx-driven runs. NR2 Timing uses sys_clock_gettime (monotonic, ns precision) not wall-clock -- resilient to NTP adjustments mid-run. NR3 Each bench's child process spawned via fork + execve; output redirected to /dev/null via dup3 so measurements aren't I/O-bottlenecked. NR4 Exit codes propagate: if any child exits non-zero, the whole harness exits non-zero (CI-friendly).