Rework busybox build process, remove compressed includes

Like the kernel, use an output folder to generate includes

Signed-off-by: Tanguy Pruvot <tanguy.pruvot@gmail.com>

Change-Id: I988675b071c7a9a959598734fdaff1fdda4e274f
darwin: fix make prepare, force prebuilt host compiler

android: fix makefile to build on AOSP

current AOSP (master) seems a bit different regarding
the variable $(TARGET_OUT_INTERMEDIATES)

Change-Id: Iffc3dfb1f015263ad32447fa5b8855fb54560562
Android.mk: toggle l-preview config flag