allow overriding python location during builds using .buckconfig or .…

…buckconfig.local (only applies to Windows)

rake-tasks/buck.rb

@@ -1,3 +1,4 @@
+require 'inifile'
 require 'open3'
 require 'rake-tasks/checks'
 
@@ -46,7 +47,15 @@ def self.download
       org.apache.http.util.EntityUtils.consume(entity) unless entity.nil?
 
       File.chmod(0755, out)
-      cmd = (windows?) ? ["python", out] : [out]
+
+      cmd = if windows?
+              buckconfigs = [IniFile.load('.buckconfig.local'), IniFile.load('.buckconfig')]
+              python_interpreter = buckconfigs.lazy.map { |c| c && c['parser']['python_interpreter'] }.find(&:itself)
+              [python_interpreter || "python", out]
+            else
+              [out]
+            end
+
       sh cmd.join(" ") + " kill", :verbose => true
       cmd
     )