title: aidl is missing android studio
body: <pre><code>Environment:
  Mac OS 10.10.3
  Android studio:1.2.11
  grandle:2.2.1
  </code></pre>
  
  <p>the log：</p>
  
  <pre><code>Information:Gradle tasks [:generateDebugSources, :generateDebugTestSources]
  :preBuild
  :preDebugBuild
  :checkDebugManifest
  :prepareDebugDependencies
  :compileDebugAidl FAILED
  Error:Execution failed for task ':compileDebugAidl'.
  &gt; aidl is missing
  </code></pre>
  
  <p>&nbsp;</p>
  
  <pre><code>// Top-level build file where you can add configuration options common to all sub-projects/modules.
  import org.gradle.internal.os.OperatingSystem
  buildscript {
      repositories {
          jcenter()
      }
      dependencies {
          classpath 'com.android.tools.build:gradle:1.0.0'
      }
  }
  
  allprojects {
      repositories {
          jcenter()
      }
  }
  String SDK_DIR = System.getenv("ANDROID_HOME")
  if(SDK_DIR == null) {
      Properties props = new Properties()
      props.load(new FileInputStream(project.rootProject.file("local.properties")))
      SDK_DIR = props.get('sdk.dir');
  }
  
  
  apply plugin: 'com.android.application'
  
  android {
      compileSdkVersion 21
      buildToolsVersion "21.1.1"
  
      sourceSets {
          main {
              manifest.srcFile 'AndroidManifest.xml'
              java.srcDirs = ['src']
              resources.srcDirs = ['src']
              aidl.srcDirs = ['src']
              renderscript.srcDirs = ['src']
              res.srcDirs = ['res']
              assets.srcDirs = ['assets']
              jniLibs.srcDirs = ['libs']
          }
  
          // Move the tests to tests/java, tests/res, etc...
          instrumentTest.setRoot('tests')
  
          // Move the build types to build-types/&lt;type&gt;
          // For instance, build-types/debug/java, build-types/debug/AndroidManifest.xml, ...
          // This moves them out of them default location under src/&lt;type&gt;/... which would
          // conflict with src/ being used by the main source set.
          // Adding new build types or product flavors should be accompanied
          // by a similar customization.
          debug.setRoot('build-types/debug')
          release.setRoot('build-types/release')
      }
      defaultConfig {
          minSdkVersion 14
          targetSdkVersion 21
      }
  
      buildTypes {
          release {
              proguardFiles 'proguard.cfg'
          }
      }
  
      lintOptions {
          checkReleaseBuilds false
          // Or, if you prefer, you can continue to check for errors in release builds,
          // but continue the build even when errors are found:
          abortOnError false
      }
  }
  
  dependencies {
      compile fileTree(include: '*.jar', dir: 'libs')
  
      provided files("${SDK_DIR}/platforms/android-17/data/layoutlib.jar")
      //compile files('libs/pass-v1.1.3.jar')
     // compile files('libs/sdk-v1.0.0.jar')
  }
  </code></pre>
  
  <p>before this, I had compile the android resource 4.4 on my Mac, and modified some files in OS system, I think it is the reason is that, but I've forget which file, Someone encountered this problem yet</p>