Issue 8051. Make extended exit codes optional.

compiler/java/com/google/dart/compiler/DartCompiler.java

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 package com.google.dart.compiler;
 
 import com.google.common.base.Objects;
 import com.google.common.collect.Maps;
 import com.google.common.collect.Sets;
 import com.google.common.collect.Sets.SetView;
@@ skipping 1050 matching lines @@
             return compilerMain(compilerOptions);
           }
         });
       } else {
         result = compilerMain(topCompilerOptions);
       }
     } catch (Throwable t) {
       t.printStackTrace();
       crash();
     }
-    System.exit(result.code);
+    // exit
+    {
+      int exitCode = result.code;
+      if (!topCompilerOptions.extendedExitCode()) {
+        if (exitCode == RESULT_ERRORS) {
+          exitCode = 1;
+        } else {
+          exitCode = 0;
+        }
+      }
+      System.exit(exitCode);
+    }
   }
 
   /**
    * Invoke the compiler to build single application.
    * 
    * @param compilerOptions parsed command line arguments
    * @return the result as integer when <code>0</code> means clean; <code>1</code> there were
    *         warnings; <code>2</code> there were errors; <code>127</code> other problems or
    *         exceptions.
    */
@@ skipping 357 matching lines @@
           return br.readLine();
         } finally {
           br.close();
         }
       }
     } catch (Throwable e) {
     }
     return null;
   }
 }