gnu: ruby: Update to 2.3.1.

* gnu/packages/ruby.scm (ruby): Update to 2.3.1.
[origin] Add symlink patch.
* gnu/packages/patches/ruby-symlinkfix.patch: New file.
* gnu/local.mk (dist_patch_DATA): Add patch.

gnu/local.mk

@@ -723,6 +723,7 @@ dist_patch_DATA =						\
   gnu/packages/patches/readline-link-ncurses.patch		\
   gnu/packages/patches/ripperx-missing-file.patch		\
   gnu/packages/patches/rsem-makefile.patch			\
+  gnu/packages/patches/ruby-symlinkfix.patch                    \
   gnu/packages/patches/sed-hurd-path-max.patch			\
   gnu/packages/patches/scheme48-tests.patch			\
   gnu/packages/patches/scotch-test-threading.patch		\

gnu/packages/patches/ruby-symlinkfix.patch

@@ -0,0 +1,53 @@
+Fix symlinks to '..' to fix rubygems improperly expanding symlinked
+paths. Without this fix, some gems fail to install. This patch is applied in
+rubygems 2.5.2, but ruby version 2.3.1 bundles an older version of rubygems
+(2.5.1).
+
+--- a/lib/rubygems/package.rb
++++ b/lib/rubygems/package.rb
+@@ -383,7 +383,7 @@ def extract_tar_gz io, destination_dir, pattern = "*" # :nodoc:
+           FileUtils.chmod entry.header.mode, destination
+         end if entry.file?
+
+-        File.symlink(install_location(entry.header.linkname, destination_dir), destination) if entry.symlink?
++        File.symlink(entry.header.linkname, destination) if entry.symlink?
+
+         verbose destination
+       end
+diff --git a/test/rubygems/test_gem_package.rb b/test/rubygems/test_gem_package.rb
+index 7848bc2..f287bd3 100644
+--- a/test/rubygems/test_gem_package.rb
++++ b/test/rubygems/test_gem_package.rb
+@@ -428,19 +428,25 @@ def test_extract_tar_gz_absolute
+                  "#{@destination} is not allowed", e.message)
+   end
+
+-  def test_extract_tar_gz_symlink_absolute
++  def test_extract_tar_gz_symlink_relative_path
++    skip 'symlink not supported' if Gem.win_platform?
++
+     package = Gem::Package.new @gem
+
+     tgz_io = util_tar_gz do |tar|
+-      tar.add_symlink 'code.rb', '/absolute.rb', 0644
++      tar.add_file    'relative.rb', 0644 do |io| io.write 'hi' end
++      tar.mkdir       'lib',         0755
++      tar.add_symlink 'lib/foo.rb', '../relative.rb', 0644
+     end
+
+-    e = assert_raises Gem::Package::PathError do
+-      package.extract_tar_gz tgz_io, @destination
+-    end
++    package.extract_tar_gz tgz_io, @destination
+
+-    assert_equal("installing into parent path /absolute.rb of " +
+-                 "#{@destination} is not allowed", e.message)
++    extracted = File.join @destination, 'lib/foo.rb'
++    assert_path_exists extracted
++    assert_equal '../relative.rb',
++                 File.readlink(extracted)
++    assert_equal 'hi',
++                 File.read(extracted)
+   end
+
+   def test_extract_tar_gz_directory

gnu/packages/ruby.scm

@@ -46,7 +46,7 @@
 (define-public ruby
   (package
     (name "ruby")
-    (version "2.3.0")
+    (version "2.3.1")
     (source
      (origin
        (method url-fetch)
@@ -55,8 +55,9 @@
                            "/ruby-" version ".tar.xz"))
        (sha256
         (base32
-         "15s0dsb5ynf3d2w5gzawnszq5594fqvapv2y7a0qw16przq5l4kh"))
+         "0f3395q7pd2hrl2gv26bib80038sjawxgmhl9zn22fjs9m9va9b7"))
        (modules '((guix build utils)))
+       (patches (search-patches "ruby-symlinkfix.patch"))
        (snippet `(begin
                    ;; Remove bundled libffi
                    (delete-file-recursively