BUG/MEDIUM: threads: Fiw build when using no thread

In thread_detect_count(), avoid any usage of thread_cpu_enable_at_boot
if we're building without thread support. That variable is only defined
when building with threads, and those tests make little sense when
building with no thread, anyway.
This was submitted by: ririnto <ririnto@kakao.com>
This should fix github issue #3408.
This should be backported to 3.4.

diff --git a/src/thread.c b/src/thread.c
index 57f4b5aec2d5fd5e8585773824a11e34cab269d6..6c636d75d943f816339d6eead84d90c131b50dfb 100644 (file)
--- a/src/thread.c
+++ b/src/thread.c
@@ -1667,7 +1667,9 @@ void thread_detect_count(void)
        char *err __maybe_unused;
        int thr_forced = 0;
        int tgrp_forced = 0;
+#ifdef USE_THREAD
        int cpus_detected = 0;
+#endif
 
        thr_min = 1; thr_max = MAX_THREADS;
        grp_min = 1; grp_max = MAX_TGROUPS;
@@ -1810,6 +1812,7 @@ void thread_detect_count(void)
        if (!global.nbtgroups)
                global.nbtgroups = grp_min;
 
+#ifdef USE_THREAD
        if (tgrp_forced && !thr_forced && !cpu_map_in_conf &&
            (!global.thread_limit || (global.nbthread < global.thread_limit)) &&
            global.nbthread < MIN(cpus_detected, thread_cpus_enabled_at_boot) &&
@@ -1828,6 +1831,7 @@ void thread_detect_count(void)
                ha_notice("%d usable CPUs detected but 'nbthread' forced to %d (%d%%). Remove 'nbthread' for optimal tuning.\n",
                          nbcpus, global.nbthread, global.nbthread * 100 / nbcpus);
        }
+#endif
 
        if (global.nbthread > global.maxthrpertgroup * global.nbtgroups) {
                ha_diag_warning("nbthread too large or not set, found %d CPUs, limiting to %d threads (maximum is %d per thread group and %d groups). Please set nbthreads and/or increase thread-groups in the global section to silence this warning.\n",