Building Qt for Android on Windows : issues in advices

http://qt-project.org/wiki/building_qt-android_on_windows

I clone Qt 5 last week and checked out the branch 5.4.

Some environment variables are wrong :
ANDROID_NDK_PLATFORM changed to ANDROID_API_VERSION
ANDROID_SDK_ROOT is missing or if ANDROID_SDK is working too, it's necessary to indicate that the syntax <VARIABLE_NAME> represent an environment variable need to be set.

I also notice that the configure failed with the ndk9, using the ndk10d fix this.