configure.ac: stronger test for pthread linkage

We need to test linkage of pthread_create and pthread_join,
as pthread_mutex_* and pthread_key_* functions do not need
extra linkage under FreeBSD 10.3, leading to a false-positive
of the empty case.

Signed-off-by: Eric Wong <e@80x24.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/configure.ac b/configure.ac
index bbdde85c3dcca460dd0aebee6415ccce184885dc..a06177577c92b7e963cdbeb9a008bf1d7242bfa7 100644 (file)
--- a/configure.ac
+++ b/configure.ac
@@ -1083,14 +1083,19 @@ GIT_CONF_SUBST([HAVE_BSD_SYSCTL])
 AC_DEFUN([PTHREADTEST_SRC], [
 AC_LANG_PROGRAM([[
 #include <pthread.h>
+static void *noop(void *ignore) { return ignore; }
 ]], [[
        pthread_mutex_t test_mutex;
        pthread_key_t test_key;
+       pthread_t th;
        int retcode = 0;
+       void *ret = (void *)0;
        retcode |= pthread_key_create(&test_key, (void *)0);
        retcode |= pthread_mutex_init(&test_mutex,(void *)0);
        retcode |= pthread_mutex_lock(&test_mutex);
        retcode |= pthread_mutex_unlock(&test_mutex);
+       retcode |= pthread_create(&th, ret, noop, ret);
+       retcode |= pthread_join(th, &ret);
        return retcode;
 ]])])