Android: final cleanup of new build system

Rename hidden config files to busybox-<profile>.config

Set also KBUILD_OUTPUT to prevent generation of files in src dir,
if local make without O= is made (which create host code)

That do not force the rebuild of config files, except with mm -B

With the help of Chih-Wei Huang <cwhuang@linux.org.tw>

Change-Id: Ic6bc2bc7177b1f266b9c0d1ccdfb925c1aa00d46
Signed-off-by: Tanguy Pruvot <tanguy.pruvot@gmail.com>
Makefile: remove warnings on initial version check

Android.mk is using a SUBMAKE variable which is only
used to get busybox version as a CFLAG. This one has
the -s (--silent) makeflag. So ignore the KBUILD_OUTPUT
default value if this flag is present.

Change-Id: Ifcc11d148d6707a8c301b3d2ba0370b91215647e
android: backport pty implementation from aosp/master

This is not (yet) in l-preview branch but on master
The only way to prevent duplicated includes was to
test the existence of a new constant added after
l-preview bionic source release.

Also use compatible hasmntopt() return type
(swapon/off compilation warnings)

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

Change-Id: I4ee6e7752eab84de4566ae86a90171b8241fcaea
Fix remaining bionic warnings

Tested on arm and x86 (kitkat),
aosp/master has some other ones

Also update the readme and android.h

Change-Id: I170b16f2e091b99f971fb518bf0106c0e92adfdd
Merge remote-tracking branch 'cm/cm-11.0' into kk4.4