xap_helper: reset getopt(3) properly in workers

I only noticed this while doing a full -cindex --associate with
--associate-date-range=30.years.ago and --associate-max=-1 (no
limit for Xapian) between local mirrors of lore and
git.kernel.org my glibc-based system.

Apparently, glibc requires `optind = 0' to reset getopt(3) in
our workers.  Oddly, glibc appeared to work fine prior to this
change for the defaults (--associate-date-range=1.year.ago..
and --associate-max=50000).

BSDs and musl have an `optreset' variable which appear to do
the same thing, but I don't have space on BSD VMs to test full
associations.

While we're at it, we'll also keep `opterr' enabled to improve
error reporting.

diff --git a/lib/PublicInbox/xap_helper.h b/lib/PublicInbox/xap_helper.h
index fafb392d47786b4621340f1fbb784ab84efcb292..8602170fb5aa9bab0e04edf0c81ef9a1153f02a0 100644 (file)
--- a/lib/PublicInbox/xap_helper.h
+++ b/lib/PublicInbox/xap_helper.h
@@ -58,6 +58,12 @@
 #      define SET_MAX_EXPANSION set_max_wildcard_expansion
 #endif
 
+#if defined(__GLIBC__)
+#      define MY_DO_OPTRESET() do { optind = 0; } while (0)
+#else /* FreeBSD, musl, dfly, NetBSD, OpenBSD */
+#      define MY_DO_OPTRESET() do { optind = optreset = 1; } while (0)
+#endif
+
 #if defined(__FreeBSD__) || defined(__GLIBC__)
 #      define STDERR_ASSIGNABLE (1)
 #else
@@ -807,9 +813,9 @@ static void dispatch(struct req *req)
        fwrite(&req->argv[0], offsetof(struct srch, paths), 1, kfp);
 
        // global getopt variables:
-       optind = 1;
-       opterr = optopt = 0;
+       optopt = 0;
        optarg = NULL;
+       MY_DO_OPTRESET();
 
        // keep sync with @PublicInbox::XapHelper::SPEC
        while ((c = getopt(req->argc, req->argv, "acd:k:m:o:rtA:O:T:")) != -1) {