ANDROID_BUILD_TOP is deprecated

ANDROID_BUILD_TOP variable is deprecated and thus all paths are assumed
to be relative to the top directory. However, this is causing problem
when some of the paths are constructed in the Android build system and
used in the non-Android makefiles that are usually executed NOT at the
top directory but at a sub directory using -C option. As a result, the
relative path from the Android build system become invalid in the
non-Android makefiles.
In order to overcome the restriction, ANDROID_BUILD_TOP is manually
constructed when invoking the non-Android makefiles by using $$(pwd).
The non-Android makefiles are expected to construct the absolute path
by prepending ANDROID_BUILD_TOP to any path that came from the Android
build system.

Change-Id: Ia2e380cf329f56c8d36ad8dbde90d6a655f9509a
Signed-off-by: Divya Sharma <divyash@codeaurora.org>
Signed-off-by: Bruce Levy <blevy@codeaurora.org>
Signed-off-by: Prasad Sodagudi <psodagud@codeaurora.org>
Signed-off-by: David Ng <dave@codeaurora.org>