fix(Makefile): prevent NUM_VALIDATORS from evaluating to two tokens - #339

Disclosure: I’m an external community contributor, not affiliated with Circle, not a maintainer, and I have no write access to this repository.

This is advisory review only.\n\nI independently re-ran the old and new Makefile expressions against the three relevant manifest states, plus a missing-file control:\n\n| manifest | old expression | this PR |\n|---|---:|---:|\n| missing file | 5 | 5 |\n| existing file with no validator sections | 0 5 | 5 |\n| existing file with three validator sections | 3 | 3 |\n\nThe reported bug is real, and the patch fixes the actual failure without changing the existing fallback policy. The important detail is that GNU grep -c prints 0 but exits with status 1 when there are no matches; the old || echo 5 therefore appended a second value.

The revised shell conditional treats a positive count as authoritative and falls back only for an empty/zero/non-numeric result.\n\nThe shell syntax is POSIX-compatible (make invokes /bin/sh here), and QUAKE_MANIFEST remains recursively expanded, so targets that override the manifest still recompute NUM_VALIDATORS as intended. I also checked the current Makefile usage: the value is passed as the single --num-validators argument to the genesis command, so eliminating the second token directly removes the malformed invocation.\n\nI did not find a correctness issue in the three-line change. The three cases in the PR description are the right regression matrix; the missing-file case is a useful control because it confirms the fallback behavior was not accidentally changed. This looks ready from the code/behavior side, subject to the repository’s normal CI/maintainer review.