Change go.rb to update it to 1.8.3 and add check method.

Change go.rb to check installed go instead of using `which go` for the ease of use.
Change go.rb to use `cp` instead of `mv` to perform testing correctly.

packages/go.rb

@@ -3,39 +3,49 @@ require 'package'
 class Go < Package
   description 'Go is an open source programming language that makes it easy to build simple, reliable, and efficient software.'
   homepage 'https://golang.org/'
-  version '1.8.0'
-  source_url 'https://storage.googleapis.com/golang/go1.8.src.tar.gz'
-  source_sha1 '37945c372140c3a46c2c5b4b9ce382b6c8d88811'
+  version '1.8.3'
+  source_url 'https://storage.googleapis.com/golang/go1.8.3.src.tar.gz'
+  source_sha1 '7c3b942c58a44396ff1d205d0e6e72770792d626'
   
+  # Tests requires perl
+  depends_on 'perl'
   # go is required to build versions of go > 1.4
-  if `which go` == ''
+  unless File.exist? "#{CREW_PREFIX}/lib/go/bin/go"
     depends_on 'go_bootstrap'
   end
 
   def self.build
     FileUtils.cd('src') do
       # install with go_bootstrap if go is not in the path
-      if `which go` == ''
-        system "GOROOT_BOOTSTRAP=/usr/local/lib/go_bootstrap/go \
-                TMPDIR=/usr/local/tmp \
+      unless File.exist? "#{CREW_PREFIX}/lib/go/bin/go"
+        system "GOROOT_BOOTSTRAP=#{CREW_PREFIX}/lib/go_bootstrap/go \
+                TMPDIR=#{CREW_PREFIX}/tmp \
                 ./make.bash"
       else
-        system "GOROOT_BOOTSTRAP=/usr/local/lib/go \
-                TMPDIR=/usr/local/tmp ./make.bash"
+        system "GOROOT_BOOTSTRAP=#{CREW_PREFIX}/lib/go \
+                TMPDIR=#{CREW_PREFIX}/tmp ./make.bash"
       end
     end
   end
 
   def self.install
-    dest = "#{CREW_DEST_DIR}/usr/local/lib/"
+    dest = "#{CREW_DEST_DIR}#{CREW_PREFIX}/lib/"
     system "mkdir", "-p", dest
-    FileUtils.mv Dir.pwd, dest
+    FileUtils.cp_r Dir.pwd, dest
 
     puts "--------"
-    puts "Installed Go for #{ARCH} in /usr/local/lib/go"
+    puts "Installed Go for #{ARCH} in #{CREW_PREFIX}/lib/go"
     puts "Make sure to set go environment variables."
     puts "Minimal:"
-    puts "\texport GOROOT=/usr/local/lib/go"
+    puts "\texport GOROOT=#{CREW_PREFIX}/lib/go"
     puts "\texport PATH=$PATH:$GOROOT/bin"
+    puts "To use `go run`:"
+    puts "\texport TMPDIR=#{CREW_PREFIX}/tmp"
+  end
+
+  def self.check
+    FileUtils.cd('src') do
+      system "PATH=\"#{Dir.pwd}/../bin:$PATH\" TMPDIR=\"#{CREW_PREFIX}/tmp\" go tool dist test"
+    end
   end
 end