title: downgrade android support library , Building mozilla fennec
body: <p>I am trying to Build Firefox for Android. 
  I followed all the instructions here: <a href="https://wiki.mozilla.org/Mobile/Fennec/Android#Android_NDK_and_SDK_version_notes" rel="nofollow">https://wiki.mozilla.org/Mobile/Fennec/Android#Android_NDK_and_SDK_version_notes</a></p>
  
  <p>I ran <code>./mach Build</code>, the terminal shows the following error: </p>
  
  <pre><code>193:09.18 Found 1 drawables in '/home/himani/mozilla-central/mobile/android/base/resources' for 'webmaker': ['drawable-xhdpi/suggestedsites_webmaker.png']
  193:09.18 Found 1 drawables in '/home/himani/mozilla-central/mobile/android/base/resources' for 'restricted_mozilla': ['drawable-xhdpi/suggestedsites_restricted_mozilla.png']
  193:09.19 /home/himani/mozilla-central/obj-arm-linux-androideabi/mobile/android/base/res/raw/suggestedsites.json updated
  193:09.45 Read 3 engines: [u'Google', u'Yahoo', u'Bing']
  193:09.45 Default engine is 'Google'.
  193:09.45 Region 'US': Read 3 engines: [u'Yahoo', u'Google', u'Bing']
  193:09.45 Region 'US': Default engine is 'Yahoo'.
  193:09.46 /home/himani/mozilla-central/obj-arm-linux-androideabi/mobile/android/base/res/raw/browsersearch.json updated
  193:10.08 gecko-thirdparty.jar
  193:10.49 sync-thirdparty.jar
  193:13.66 Note: /home/himani/mozilla-central/mobile/android/base/SysInfo.java uses or overrides a deprecated API.
  193:13.66 Note: Recompile with -Xlint:deprecation for details.
  193:27.64 Note: Some input files use or override a deprecated API.
  193:27.64 Note: Recompile with -Xlint:deprecation for details.
  193:27.65 Note: Some input files use unchecked or unsafe operations.
  193:27.65 Note: Recompile with -Xlint:unchecked for details.
  193:30.13 geckoview_resources.zip
  193:31.97 gecko-mozglue.jar
  193:33.38     (skipping file '.mkdir.done' due to ANDROID_AAPT_IGNORE pattern '.*')
  193:33.38     (skipping file '.mkdir.done' due to ANDROID_AAPT_IGNORE pattern '.*')
  193:44.11 /home/himani/.mozbuild/android-sdk-linux/extras/android/support/v7/appcompat/res/values-v23/styles_base.xml:20: error: Error retrieving parent for item: No resource found that matches the given name 'android:Widget.Material.Button.Colored'.
  193:44.11 
  193:44.11 /home/himani/.mozbuild/android-sdk-linux/extras/android/support/v7/appcompat/res/values-v23/styles_base_text.xml:19: error: Error retrieving parent for item: No resource found that matches the given name 'android:TextAppearance.Material.Widget.Button.Inverse'.
  193:44.11 
  193:44.20 make[5]: *** [.aapt.deps] Error 1
  193:44.20 make[5]: *** Deleting file `.aapt.deps'
  193:44.20 make[5]: *** Waiting for unfinished jobs....
  193:47.91 Note: Some input files use or override a deprecated API.
  193:47.92 Note: Recompile with -Xlint:deprecation for details.
  193:47.92 Note: Some input files use unchecked or unsafe operations.
  193:47.92 Note: Recompile with -Xlint:unchecked for details.
  193:48.83 make[4]: *** [mobile/android/base/libs] Error 2
  193:48.83 make[3]: *** [libs] Error 2
  193:48.83 make[2]: *** [default] Error 2
  193:48.84 make[1]: *** [realbuild] Error 2
  193:48.84 make: *** [build] Error 2
  </code></pre>
  
  <p>Now, I think the problem arises because the Android build SDK and Support library versions are different. But I am not being able to downgrade my support library to an earlier version. 
  Can anyone suggest me a way to do that?</p>