net/mosquitto: restore libressl support

The mosquitto commit that added OpenSSL 1.1.0 support simultaneously
broke LibreSSL support.  This patch comes from a fork and hasn't been
incorporated upstream yet (pull request #280 still outstanding but
should eventually be merged in).

LibreSSL support broke during the version upgrade last month.

Approved by:	SSL blanket

net/mosquitto/files/patch-support-libressl

@@ -0,0 +1,68 @@
+From 9f74e09373f3be7b77f510ef8b0ae2c887f7b325 Mon Sep 17 00:00:00 2001
+From: Natanael Copa <ncopa@alpinelinux.org>
+Date: Tue, 4 Oct 2016 14:35:33 +0200
+Subject: [PATCH] [280] Fix build with libressl
+
+Closes #280
+
+Fix building with libressl which broke in commit fff741613 (Support for
+openssl 1.1.0).
+
+Bug: #280
+
+Signed-off-by: Natanael Copa <ncopa@alpinelinux.org>
+---
+ lib/mosquitto_internal.h | 3 +++
+ src/mosquitto_passwd.c   | 4 ++--
+ src/security_default.c   | 2 +-
+ 3 files changed, 6 insertions(+), 3 deletions(-)
+
+diff --git lib/mosquitto_internal.h lib/mosquitto_internal.h
+index 4b4cf85..700bbb0 100644
+--- lib/mosquitto_internal.h
++++ lib/mosquitto_internal.h
+@@ -25,6 +25,9 @@ and the Eclipse Distribution License is available at
+ 
+ #ifdef WITH_TLS
+ #  include <openssl/ssl.h>
++#  if OPENSSL_VERSION_NUMBER >= 0x10100000L && !defined(LIBRESSL_VERSION_NUMBER)
++#    define HAVE_OPENSSL_OPAQUE_STRUCTS
++#  endif
+ #else
+ #  include <time.h>
+ #endif
+diff --git src/mosquitto_passwd.c src/mosquitto_passwd.c
+index de9a719..5b854d9 100644
+--- src/mosquitto_passwd.c
++++ src/mosquitto_passwd.c
+@@ -90,7 +90,7 @@ int output_new_password(FILE *fptr, const char *username, const char *password)
+ 	unsigned char hash[EVP_MAX_MD_SIZE];
+ 	unsigned int hash_len;
+ 	const EVP_MD *digest;
+-#if OPENSSL_VERSION_NUMBER < 0x10100000L
++#ifndef HAVE_OPENSSL_OPAQUE_STRUCTS
+ 	EVP_MD_CTX context;
+ #else
+ 	EVP_MD_CTX *context;
+@@ -117,7 +117,7 @@ int output_new_password(FILE *fptr, const char *username, const char *password)
+ 		return 1;
+ 	}
+ 
+-#if OPENSSL_VERSION_NUMBER < 0x10100000L
++#ifndef HAVE_OPENSSL_OPAQUE_STRUCTS
+ 	EVP_MD_CTX_init(&context);
+ 	EVP_DigestInit_ex(&context, digest, NULL);
+ 	EVP_DigestUpdate(&context, password, strlen(password));
+diff --git src/security_default.c src/security_default.c
+index 64ca846..9ad8708 100644
+--- src/security_default.c
++++ src/security_default.c
+@@ -770,7 +770,7 @@ int mosquitto_psk_key_get_default(struct mosquitto_db *db, const char *hint, con
+ int _pw_digest(const char *password, const unsigned char *salt, unsigned int salt_len, unsigned char *hash, unsigned int *hash_len)
+ {
+ 	const EVP_MD *digest;
+-#if OPENSSL_VERSION_NUMBER < 0x10100000L
++#ifndef HAVE_OPENSSL_OPAQUE_STRUCTS
+ 	EVP_MD_CTX context;
+ 
+ 	digest = EVP_get_digestbyname("sha512");