From 53b3be4ee9e814a22876675c0ee004f0ebfb8535 Mon Sep 17 00:00:00 2001
From: yuangongji <82787816@qq.com>
Date: Sat, 26 Oct 2019 22:31:18 +0800
Subject: [PATCH] autotools: fails build when need but can not find openssl

---
 m4/libevent_openssl.m4 | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/m4/libevent_openssl.m4 b/m4/libevent_openssl.m4
index 19811981..a5ea6762 100644
--- a/m4/libevent_openssl.m4
+++ b/m4/libevent_openssl.m4
@@ -47,6 +47,11 @@ case "$enable_openssl" in
     AC_SUBST(OPENSSL_LIBS)
     case "$have_openssl" in
      yes)  AC_DEFINE(HAVE_OPENSSL, 1, [Define if the system has openssl]) ;;
+     *) AC_MSG_ERROR([openssl is a must but can not be found. You should add the \
+directory containing `openssl.pc' to the `PKG_CONFIG_PATH' environment variable, \
+or set `CFLAGS' and `LDFLAGS' directly for openssl, or use `--disable-openssl' \
+to disable support for openssl encryption])
+	;;
     esac
     ;;
 esac
-- 
2.40.0