--- /dev/null
+From 0374b55942e533a3c3997439481a8d05d6c8f729 Mon Sep 17 00:00:00 2001
+From: Fabrice Fontaine <fontaine.fabrice@gmail.com>
+Date: Sat, 8 Jun 2019 23:44:37 +0200
+Subject: [PATCH] m4/libevent_openssl.m4: fix detection of openssl
+
+Since commit 506df426dbeb0187bbd3654bd286b4100628fb16, OPENSSL_INCS is
+added to CPPFLAGS without any white space, as a result openssl detection
+fails on:
+configure:10395: checking openssl/ssl.h usability
+configure:10395: /home/fabrice/buildroot-test/buildroot/output/host/bin/riscv32-linux-gcc -c -D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64 -Os -Wall -fno-strict-aliasing -D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64-I/home/fabrice/buildroot-test/buildroot/output/host/bin/../riscv32-buildroot-linux-gnu/sysroot/usr/include conftest.c >&5
+<command-line>:0:0: warning: "_FILE_OFFSET_BITS" redefined
+<command-line>:0:0: note: this is the location of the previous definition
+<command-line>:0:23: error: division by zero in #if
+
+Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
+[Upstream status: https://github.com/libevent/libevent/pull/830]
+---
+ m4/libevent_openssl.m4 | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+diff --git a/m4/libevent_openssl.m4 b/m4/libevent_openssl.m4
+index 7b458134..19811981 100644
+--- a/m4/libevent_openssl.m4
++++ b/m4/libevent_openssl.m4
+@@ -40,7 +40,7 @@ case "$enable_openssl" in
+ ;;
+ esac
+ CPPFLAGS_SAVE=$CPPFLAGS
+- CPPFLAGS+=$OPENSSL_INCS
++ CPPFLAGS="$CPPFLAGS $OPENSSL_INCS"
+ AC_CHECK_HEADERS([openssl/ssl.h], [], [have_openssl=no])
+ CPPFLAGS=$CPPFLAGS_SAVE
+ AC_SUBST(OPENSSL_INCS)
+--
+2.20.1
+