From 5afc4e3cd855e7726a2b614d7004699ed727ec0d Mon Sep 17 00:00:00 2001
From: kinichiro <kinichiro.inoguchi@gmail.com>
Date: Sun, 16 Jul 2017 23:39:42 +0900
Subject: [PATCH] add prototype definitions of asprintf and vasprintf for
 CYGWIN build

- define _GNU_SOURCE in case of cygwin

As compilation warning report by @Dravion
---
 m4/check-os-options.m4 | 1 +
 1 file changed, 1 insertion(+)

diff --git a/m4/check-os-options.m4 b/m4/check-os-options.m4
index 77b069f..4f56a8d 100644
--- a/m4/check-os-options.m4
+++ b/m4/check-os-options.m4
@@ -13,6 +13,7 @@ case $host_os in
 		;;
 	*cygwin*)
 		HOST_OS=cygwin
+		CPPFLAGS="$CPPFLAGS -D_GNU_SOURCE"
 		;;
 	*darwin*)
 		HOST_OS=darwin