[ruby/pathname] Expose Pathname::VERSION

https://github.com/ruby/pathname/commit/2b0b1a82ee

ext/pathname/lib/pathname.rb

@@ -14,6 +14,8 @@ require 'pathname.so'
 
 class Pathname
 
+  VERSION = "0.2.1"
+
   # :stopdoc:
 
   # to_path is implemented so Pathname objects are usable with File.open, etc.

ext/pathname/pathname.gemspec

@@ -1,6 +1,13 @@
+name = File.basename(__FILE__, ".gemspec")
+version = ["lib", "ext/lib"].find do |dir|
+  break File.foreach(File.join(__dir__, dir, "#{name}.rb")) do |line|
+    /^\s*VERSION\s*=\s*"(.*)"/ =~ line and break $1
+  end rescue nil
+end
+
 Gem::Specification.new do |spec|
-  spec.name          = "pathname"
-  spec.version       = "0.2.1"
+  spec.name          = name
+  spec.version       = version
   spec.authors       = ["Tanaka Akira"]
   spec.email         = ["akr@fsij.org"]