gnu: libssh: Update to 0.8.6.

* gnu/packages/patches/libssh-hostname-parser-bug.patch: Remove.
* gnu/local.mk (dist_patch_DATA): Adjust accordingly.
* gnu/packages/ssh.scm (libssh): Update to 0.8.6.
[source](patches): Remove.
[arguments]: Add #:phases.
(guile-ssh)[source](modules, snippet]: New fields.

gnu/local.mk

@@ -933,7 +933,6 @@ dist_patch_DATA =						\
   %D%/packages/patches/libsndfile-CVE-2017-8361-8363-8365.patch	\
   %D%/packages/patches/libsndfile-CVE-2017-8362.patch		\
   %D%/packages/patches/libsndfile-CVE-2017-12562.patch		\
-  %D%/packages/patches/libssh-hostname-parser-bug.patch		\
   %D%/packages/patches/libssh2-fix-build-failure-with-gcrypt.patch	\
   %D%/packages/patches/libtar-CVE-2013-4420.patch 		\
   %D%/packages/patches/libtheora-config-guess.patch		\

gnu/packages/patches/libssh-hostname-parser-bug.patch

@@ -1,17 +0,0 @@
-It does not handle the case for the unsupported opcode (-1)
-which would cause a segfault when accessing the "seen" array.
-
-diff --git a/src/config.c b/src/config.c
-index c5313ec8..72e07639 100644
---- a/src/config.c
-+++ b/src/config.c
-@@ -218,7 +218,8 @@ static int ssh_config_parse_line(ssh_session session, const char *line,
-   }
- 
-   opcode = ssh_config_get_opcode(keyword);
--  if (*parsing == 1 && opcode != SOC_HOST) {
-+  if (*parsing == 1 && opcode != SOC_HOST &&
-+      opcode > SOC_UNSUPPORTED && opcode < SOC_END) {
-       if (seen[opcode] != 0) {
-           return 0;
-       }

gnu/packages/ssh.scm

@@ -1,5 +1,5 @@
 ;;; GNU Guix --- Functional package management for GNU
-;;; Copyright © 2012, 2013, 2014, 2015, 2016, 2017, 2018 Ludovic Courtès <ludo@gnu.org>
+;;; Copyright © 2012, 2013, 2014, 2015, 2016, 2017, 2018, 2019 Ludovic Courtès <ludo@gnu.org>
 ;;; Copyright © 2013, 2014 Andreas Enge <andreas@enge.fr>
 ;;; Copyright © 2014, 2015, 2016 Mark H Weaver <mhw@netris.org>
 ;;; Copyright © 2015, 2016, 2018 Efraim Flashner <efraim@flashner.co.il>
@@ -67,22 +67,31 @@
 (define-public libssh
   (package
     (name "libssh")
-    (version "0.7.7")
+    (version "0.8.6")
     (source (origin
               (method git-fetch)
               (uri (git-reference
                      (url "https://git.libssh.org/projects/libssh.git")
                      (commit (string-append "libssh-" version))))
-              (patches (search-patches "libssh-hostname-parser-bug.patch"))
               (sha256
                (base32
-                "07adxvhmnaq2l7sq7sn4sjlikbm1zdicq8lavq5yfila6jbx9z1y"))
+                "0rq57gpmdawljx7hqya4ipzsfpcbr31yy60kl5qv66krc9wimqda"))
               (file-name (git-file-name name version))))
     (build-system cmake-build-system)
     (outputs '("out" "debug"))
     (arguments
      '(#:configure-flags '("-DWITH_GCRYPT=ON")
 
+       #:phases (modify-phases %standard-phases
+                  (add-before 'configure 'avoid-werror
+                    (lambda _
+                      ;; Avoid '-Werror'.  Presumably this works fine with
+                      ;; gcc@8 on x86_64 but leads to errors with our older
+                      ;; compiler.
+                      (substitute* "CompilerChecks.cmake"
+                        (("-Werror=") "-W"))
+                      #t)))
+
        ;; TODO: Add 'CMockery' and '-DWITH_TESTING=ON' for the test suite.
        #:tests? #f))
     (inputs `(("zlib" ,zlib)
@@ -235,7 +244,22 @@ Additionally, various channel-specific options can be negotiated.")
               (file-name (string-append name "-" version ".tar.gz"))
               (sha256
                (base32
-                "1g2jzcg1p25zrkx06j160qb8bgcwa3001ys4q02496xs61pvywqk"))))
+                "1g2jzcg1p25zrkx06j160qb8bgcwa3001ys4q02496xs61pvywqk"))
+              (modules '((guix build utils)))
+              (snippet
+               '(begin
+                  ;; libssh >= 0.8.0 no longer provides libssh_threads: see
+                  ;; <https://github.com/artyom-poptsov/guile-ssh/issues/9>.
+                  (substitute* "libguile-ssh/Makefile.am"
+                    (("-lssh_threads") ""))
+
+                  ;; This test would wrongfully pick DSS keys when running on
+                  ;; libssh >= 0.8.0, which fails:
+                  ;; <https://github.com/artyom-poptsov/guile-ssh/issues/10>.
+                  (substitute* "tests/server.scm"
+                    (("= %libssh-minor-version 7")
+                     ">= %libssh-minor-version 7"))
+                  #t))))
     (build-system gnu-build-system)
     (outputs '("out" "debug"))
     (arguments