diff --git a/srcpkgs/opensmtpd/patches/libressl-compat.patch b/srcpkgs/opensmtpd/patches/libressl-compat.patch
new file mode 100644
index 00000000000..b201e4f6115
--- /dev/null
+++ b/srcpkgs/opensmtpd/patches/libressl-compat.patch
@@ -0,0 +1,97 @@
+From f948b923873a93472dea9b786cf60a3472b0ddc8 Mon Sep 17 00:00:00 2001
+From: Samuel Holland <samuel@sholland.org>
+Date: Wed, 11 Jan 2017 17:35:29 -0600
+Subject: [PATCH] fix compatibility with libressl
+
+These functions are exported by libcrypto from libressl, due to its
+similar OpenBSD compatibility layer, but they are not present in any
+header files. Thus, while we can use the existing compiled function,
+and do not need to provide our own, we do need to provide the prototype
+for it.
+
+This avoids implicit function declarations and the resulting crashes due
+to pointer truncation.
+
+The patch is based on an equivalent patch for OpenSSH from
+https://bugzilla.mindrot.org/show_bug.cgi?id=2465
+Also see
+https://github.com/libressl-portable/portable/issues/109
+
+Fixes #691
+---
+ openbsd-compat/defines.h        |  9 ---------
+ openbsd-compat/openbsd-compat.h | 25 +++++++++++++++----------
+ 2 files changed, 15 insertions(+), 19 deletions(-)
+
+--- openbsd-compat/defines.h
++++ openbsd-compat/defines.h
+@@ -422,15 +422,6 @@ typedef uint16_t	in_port_t;
+ #define INET6_ADDRSTRLEN 46
+ #endif
+ 
+-/*
+- * Platforms that have arc4random_uniform() and not arc4random_stir()
+- * shouldn't need the latter.
+- */
+-#if defined(HAVE_ARC4RANDOM) && defined(HAVE_ARC4RANDOM_UNIFORM) && \
+-    !defined(HAVE_ARC4RANDOM_STIR)
+-# define arc4random_stir()
+-#endif
+-
+ #ifndef HAVE_VA_COPY
+ # ifdef HAVE___VA_COPY
+ #  define va_copy(dest, src) __va_copy(dest, src)
+--- openbsd-compat/openbsd-compat.h
++++ openbsd-compat/openbsd-compat.h
+@@ -119,20 +119,25 @@ int	BSDoptind;		/* index into parent argv vector */
+ int getpeereid(int , uid_t *, gid_t *);
+ #endif 
+ 
+-#ifdef HAVE_ARC4RANDOM
+-# ifndef HAVE_ARC4RANDOM_STIR
+-#  define arc4random_stir()
+-# endif
+-#else
++#if !defined(HAVE_ARC4RANDOM) || defined(LIBRESSL_VERSION_NUMBER)
+ unsigned int arc4random(void);
++#endif
++
++#if defined(HAVE_ARC4RANDOM_STIR)
+ void arc4random_stir(void);
+-#endif /* !HAVE_ARC4RANDOM */
++#elif defined(HAVE_ARC4RANDOM) || defined(LIBRESSL_VERSION_NUMBER)
++/* Recent system/libressl implementation; no need for explicit stir */
++# define arc4random_stir()
++#else
++/* openbsd-compat/arc4random.c provides arc4random_stir() */
++void arc4random_stir(void);
++#endif
+ 
+-#ifndef HAVE_ARC4RANDOM_BUF
++#if !defined(HAVE_ARC4RANDOM_BUF) || defined(LIBRESSL_VERSION_NUMBER)
+ void arc4random_buf(void *, size_t);
+ #endif
+ 
+-#ifndef HAVE_ARC4RANDOM_UNIFORM
++#if !defined(HAVE_ARC4RANDOM_UNIFORM) || defined(LIBRESSL_VERSION_NUMBER)
+ uint32_t arc4random_uniform(uint32_t);
+ #endif
+ 
+@@ -174,7 +179,7 @@ int vasprintf(char **, const char *, va_list);
+ int vsnprintf(char *, size_t, const char *, va_list);
+ #endif
+ 
+-#ifndef HAVE_EXPLICIT_BZERO
++#if !defined(HAVE_EXPLICIT_BZERO) || defined(LIBRESSL_VERSION_NUMBER)
+ void explicit_bzero(void *p, size_t n);
+ #endif
+ 
+@@ -200,7 +205,7 @@ int pidfile(const char *basename);
+ struct passwd *pw_dup(const struct passwd *);
+ #endif
+ 
+-#ifndef HAVE_REALLOCARRAY
++#if !defined(HAVE_REALLOCARRAY) || defined(LIBRESSL_VERSION_NUMBER)
+ void *reallocarray(void *, size_t, size_t);
+ #endif
+ 
diff --git a/srcpkgs/opensmtpd/template b/srcpkgs/opensmtpd/template
index dcc6ce71fbb..49080b6e63a 100644
--- a/srcpkgs/opensmtpd/template
+++ b/srcpkgs/opensmtpd/template
@@ -1,15 +1,11 @@
 # Template file for 'opensmtpd'
 pkgname=opensmtpd
 version=6.0.2p1
-revision=4
+revision=5
 build_style=gnu-configure
 configure_args="--sysconfdir=/etc/smtpd --sbindir=/usr/bin
  --with-path-socket=/run --with-mantype=doc --with-pie --with-table-db
  --with-path-CAfile=/etc/ssl/certs/ca-certificates.crt
- ac_cv_search_arc4random=no
- ac_cv_func_arc4random=no
- ac_cv_func_arc4random_buf=no
- ac_cv_func_arc4random_uniform=no
  ac_cv_func_explicit_bzero=no
  ac_cv_func_reallocarray=no
  ac_cv_func_strlcat=no