Problema al importar el paquete android.support.v4

Estoy tratando de incluir el android-support-v4.jar en mi proyecto de androide de línea de comandos. Mi declaración de importación es simplemente:

import android.support.v4.NavUtils; 

He copiado el tarro de $ANDROID_HOME/extras/android/support/v4/android-support-v4.jar en las $ANDROID_HOME/extras/android/support/v4/android-support-v4.jar libs/ carpeta de mi proyecto pero aún así recibo el siguiente error al crear con ant :

 package android.support.v4 does not exist 

Mi comprensión es que cualquier frascos colocados en la libs/ carpeta se incluyen automáticamente en los proyectos classpath.

Según lo solicitado, la salida de ls -l en la carpeta del proyecto raíz es

 -rw-r--r-- 1 Nick staff 1192 4 Jan 15:08 AndroidManifest.xml -rw-r--r-- 1 Nick staff 696 4 Jan 12:12 ant.properties drwxr-xr-x 17 Nick staff 578 4 Jan 15:10 bin -rw-r--r-- 1 Nick staff 3922 3 Jan 14:08 build.xml drwxr-xr-x 4 Nick staff 136 3 Jan 15:11 gen drwxr-xr-x 3 Nick staff 102 4 Jan 15:18 libs -rw-r--r-- 1 Nick staff 441 3 Jan 14:08 local.properties -rw-r--r-- 1 Nick staff 781 3 Jan 14:08 proguard-project.txt -rw-r--r-- 1 Nick staff 563 3 Jan 14:08 project.properties drwxr-xr-x 8 Nick staff 272 3 Jan 14:08 res drwxr-xr-x 3 Nick staff 102 3 Jan 14:08 src 

Y toda la salida de ant debug es

  Buildfile: /Users/Nick/DEVELOPMENT/PROJECTS/MyFirstApp/build.xml -set-mode-check: -set-debug-files: -check-env: [checkenv] Android SDK Tools Revision 21.0.1 [checkenv] Installed at /Users/Nick/Development/SDKS/android-sdk-macosx -setup: [echo] Project Name: MyFirstApp [gettype] Project Type: Application -set-debug-mode: -debug-obfuscation-check: -build-setup: [echo] Resolving Build Target for MyFirstApp... [gettarget] Project Target: Android 4.2 [gettarget] API level: 17 [echo] ---------- [echo] Creating output directories if needed... [echo] ---------- [echo] Resolving Dependencies for MyFirstApp... [dependency] Library dependencies: [dependency] No Libraries [echo] ---------- [echo] Building Libraries with 'debug'... [subant] No sub-builds to iterate on -pre-build: -code-gen: [mergemanifest] No changes in the AndroidManifest files. [echo] Handling aidl files... [aidl] No AIDL files to compile. [echo] ---------- [echo] Handling RenderScript files... [renderscript] No RenderScript files to compile. [echo] ---------- [echo] Handling Resources... [aapt] No changed resources. R.java and Manifest.java untouched. [echo] ---------- [echo] Handling BuildConfig class... [buildconfig] No need to generate new BuildConfig. -pre-compile: -compile: [javac] Compiling 1 source file to /Users/Nick/DEVELOPMENT/PROJECTS/MyFirstApp/bin/classes [javac] /Users/Nick/DEVELOPMENT/PROJECTS/MyFirstApp/src/com/example/myfirstapp/DisplayMessageActivity.java:9: package android.support.v4 does not exist [javac] import android.support.v4.NavUtils; [javac] ^ [javac] /Users/Nick/DEVELOPMENT/PROJECTS/MyFirstApp/src/com/example/myfirstapp/DisplayMessageActivity.java:36: cannot find symbol [javac] symbol : variable NavUtils [javac] location: class com.example.myfirstapp.DisplayMessageActivity [javac] NavUtils.navigateUpFromSameTask(this); [javac] ^ [javac] 2 errors 

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