Added gemspec of digest library.

standalone repository is https://github.com/ruby/digest
  [Misc #13771][ruby-core:82179]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@59607 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

ext/digest/digest.gemspec

@@ -0,0 +1,34 @@
+# coding: utf-8
+# frozen_string_literal: true
+
+Gem::Specification.new do |spec|
+  spec.name          = "digest"
+  spec.version       = "0.1.0"
+  spec.authors       = ["Akinori MUSHA"]
+  spec.email         = ["knu@idaemons.org"]
+
+  spec.summary       = %q{Provides a framework for message digest libraries.}
+  spec.description   = %q{Provides a framework for message digest libraries.}
+  spec.homepage      = "https://github.com/ruby/digest"
+  spec.license       = "BSD-2-Clause"
+
+  spec.files         = [
+    ".gitignore", ".travis.yml", "Gemfile", "LICENSE.txt", "README.md", "Rakefile", "bin/console", "bin/setup",
+    "digest.gemspec", "ext/digest/bubblebabble/bubblebabble.c", "ext/digest/bubblebabble/extconf.rb", "ext/digest/defs.h",
+    "ext/digest/digest.c", "ext/digest/digest.h", "ext/digest/digest_conf.rb", "ext/digest/extconf.rb",
+    "ext/digest/md5/extconf.rb", "ext/digest/md5/md5.c", "ext/digest/md5/md5.h", "ext/digest/md5/md5cc.h",
+    "ext/digest/md5/md5init.c", "ext/digest/md5/md5ossl.h", "ext/digest/rmd160/extconf.rb", "ext/digest/rmd160/rmd160.c",
+    "ext/digest/rmd160/rmd160.h", "ext/digest/rmd160/rmd160init.c", "ext/digest/rmd160/rmd160ossl.h",
+    "ext/digest/sha1/extconf.rb", "ext/digest/sha1/sha1.c", "ext/digest/sha1/sha1.h", "ext/digest/sha1/sha1cc.h",
+    "ext/digest/sha1/sha1init.c", "ext/digest/sha1/sha1ossl.h", "ext/digest/sha2/extconf.rb", "ext/digest/sha2/lib/sha2.rb",
+    "ext/digest/sha2/sha2.c", "ext/digest/sha2/sha2.h", "ext/digest/sha2/sha2cc.h", "ext/digest/sha2/sha2init.c",
+    "ext/digest/sha2/sha2ossl.h", "ext/digest/test.sh", "ext/openssl/deprecation.rb", "lib/digest.rb"
+  ]
+  spec.bindir        = "exe"
+  spec.executables   = spec.files.grep(%r{^exe/}) { |f| File.basename(f) }
+  spec.require_paths = ["lib"]
+
+  spec.add_development_dependency "bundler"
+  spec.add_development_dependency "rake"
+  spec.add_development_dependency "rake-compiler"
+end