From 3a6ec68a328d3ab3a79a212e27f513ff1c7f6db2 Mon Sep 17 00:00:00 2001
From: David Adam <zanchey@ucc.gu.uwa.edu.au>
Date: Sat, 12 Aug 2017 14:26:40 +0800
Subject: [PATCH] Revert "configure: check that errno is threadsafe"

This reverts commit ee15f1b9877834f49342a7bd93457e423eeb2cb4.

The test relies on undefined behaviour (checking for errno in the
absence of an error condition) and was broken on OpenBSD.

Closes #4184.
---
 configure.ac | 28 ----------------------------
 1 file changed, 28 deletions(-)

diff --git a/configure.ac b/configure.ac
index abe5dafeb..bec1d582f 100644
--- a/configure.ac
+++ b/configure.ac
@@ -579,34 +579,6 @@ else
   AC_MSG_RESULT(no)
 fi
 
-# Check that threads actually work on Solaris
-AC_MSG_CHECKING([for threadsafe errno])
-AC_RUN_IFELSE(
-  [AC_LANG_PROGRAM([
-    #include <errno.h>
-    #include <pthread.h>
-    #include <signal.h>
-
-    void *thread1_func(void *p_arg)
-    {
-            errno = 1;
-            return 0;
-    }
-    ],[
-    errno = 0;
-    pthread_t t1;
-    pthread_create(&t1, NULL, thread1_func, NULL);
-    pthread_join(t1, NULL);
-    return errno;
-  ])],
-  [AC_MSG_RESULT(yes)],
-  [
-    AC_MSG_RESULT(no)
-    AC_MSG_FAILURE([errno is not threadsafe - check your compiler settings])
-  ],
-  [AC_MSG_RESULT(crosscompiling, skipped)]
-)
-
 pcre2_min_version=10.21
 EXTRA_PCRE2=
 AC_ARG_WITH(