From b35e899f494a443d4fedb768a6dbdf35835fd81d Mon Sep 17 00:00:00 2001
From: Florian Weimer <fweimer@redhat.com>
Date: Mon, 2 Jan 2023 10:38:18 +0100
Subject: [PATCH] m4: crypt_xxpg6.m4: Define _DEFAULT_SOURCE for current glibc

Current glibc no longer implements the CRYPT extension, so it does not
declare crypt in <unistd.h> in strict standard modes.  The check
defines _XOPEN_SOURCE, which enables one of these modes.  Defining
_DEFAULT_SOURCE as well again makes available the crypt function
prototype.

This avoids a configure check result change with compilers which do
not support implicit function declarations.
---
 m4/crypt_xpg6.m4 | 1 +
 1 file changed, 1 insertion(+)

diff --git a/m4/crypt_xpg6.m4 b/m4/crypt_xpg6.m4
index 0085b2ac769..3a288a3713a 100644
--- a/m4/crypt_xpg6.m4
+++ b/m4/crypt_xpg6.m4
@@ -6,6 +6,7 @@ AC_DEFUN([DOVECOT_CRYPT_XPG6], [
       #define _XOPEN_SOURCE 4
       #define _XOPEN_SOURCE_EXTENDED 1
       #define _XOPEN_VERSION 4
+      #define _DEFAULT_SOURCE
       #define _XPG4_2
       #define _XPG6
       #include <unistd.h>