Change Environment#execute() options Hash to contain :env and :options keys for Kernel#system()

spec/rscons/environment_spec.rb

@@ -219,7 +219,7 @@ module Rscons
           it "prints the short description and executes the command" do
             env = Environment.new(echo: :short)
             env.should_receive(:puts).with("short desc")
-            env.should_receive(:system).with("a", "command", {}).and_return(true)
+            env.should_receive(:system).with("a", "command").and_return(true)
             env.execute("short desc", ["a", "command"])
           end
         end
@@ -228,7 +228,7 @@ module Rscons
           it "prints the short description, executes the command, and prints the failed command line" do
             env = Environment.new(echo: :short)
             env.should_receive(:puts).with("short desc")
-            env.should_receive(:system).with("a", "command", {}).and_return(false)
+            env.should_receive(:system).with("a", "command").and_return(false)
             $stdout.should_receive(:write).with("Failed command was: ")
             env.should_receive(:puts).with("a command")
             env.execute("short desc", ["a", "command"])
@@ -240,8 +240,8 @@ module Rscons
         it "prints the command executed and executes the command" do
           env = Environment.new(echo: :command)
           env.should_receive(:puts).with("a command '--arg=val with spaces'")
-          env.should_receive(:system).with("a", "command", "--arg=val with spaces", opt: :val).and_return(false)
-          env.execute("short desc", ["a", "command", "--arg=val with spaces"], opt: :val)
+          env.should_receive(:system).with({modified: :environment}, "a", "command", "--arg=val with spaces", {opt: :val}).and_return(false)
+          env.execute("short desc", ["a", "command", "--arg=val with spaces"], env: {modified: :environment}, options: {opt: :val})
         end
       end
     end