invoke the builder's run() method

lib/rscons/builders/cc.rb

@@ -6,5 +6,8 @@ module Rscons
       'CPPFLAGS' => [],
       'OBJSUFFIX' => '.o',
     }
+
+    def run(env, sources)
+    end
   end
 end

lib/rscons/builders/program.rb

@@ -7,5 +7,8 @@ module Rscons
       'LDFLAGS' => [],
       'LIBS' => [],
     }
+
+    def run(env, sources)
+    end
   end
 end