gnu: Add squashfs-tools-next.

* gnu/packages/compression.scm (squashfs-tools-next): New variable.

gnu/packages/compression.scm

@@ -4,7 +4,7 @@
 ;;; Copyright © 2014, 2015 Mark H Weaver <mhw@netris.org>
 ;;; Copyright © 2015 Taylan Ulrich Bayırlı/Kammer <taylanbayirli@gmail.com>
 ;;; Copyright © 2015, 2016 Eric Bavier <bavier@member.fsf.org>
-;;; Copyright © 2015, 2016, 2017 Ricardo Wurmus <rekado@elephly.net>
+;;; Copyright © 2015, 2016, 2017, 2018 Ricardo Wurmus <rekado@elephly.net>
 ;;; Copyright © 2015, 2017, 2018 Leo Famulari <leo@famulari.name>
 ;;; Copyright © 2015 Jeff Mickey <j@codemac.net>
 ;;; Copyright © 2015, 2016, 2017 Efraim Flashner <efraim@flashner.co.il>
@@ -844,6 +844,23 @@ systems where low overhead is needed.  This package allows you to create and
 extract such file systems.")
     (license license:gpl2+)))
 
+;; We need this for building squashfs images with symlinks.
+(define-public squashfs-tools-next
+  (let ((commit "fb33dfc32b131a1162dcf0e35bd88254ae10e265")
+        (revision "1"))
+    (package (inherit squashfs-tools)
+      (name "squashfs-tools-next")
+      (version (string-append "4.3-" revision (string-take commit 7)))
+      (source (origin
+                (method git-fetch)
+                (uri (git-reference
+                      (url "https://github.com/plougher/squashfs-tools.git")
+                      (commit commit)))
+                (file-name (git-file-name name version))
+                (sha256
+                 (base32
+                  "1x2skf8hxzfch978nzx5mh46d4hhi6gl22270hiarjszsjk3bnsx")))))))
+
 (define-public pigz
   (package
     (name "pigz")