envsetup: set OUT_DIR to an absolute path always

OUT_DIR was set to $(TOPDIR)out previously,
but $(TOPDIR) was null, so it was a relative path.
This broke releasetools, inline kernel building, etc
since they require absolute paths.
Fix it so that it is set to $(shell readlink -f .)/out
if $(TOPDIR) is null.

Also remove hacks which checked if (OUT_DIR) was out
and changed it to $(ANDROID_BUILD_TOP)/out to workaround
the aforementioned problem.

Change-Id: I459a3b1325a1bbea0565cd73f6acf160d4ed9b39

Conflicts:
	core/base_rules.mk
	core/tasks/kernel.mk

Change-Id: I52a7a6024f0f2b708c230e53c0152ed138726cc1
ccache: Use system version over prebuilt

If there is a ccache binary on the
host system use it instead of the
AOSP prebuilt.

Change-Id: I4b1e030713be22167a12bd229a4e35eda7736cd2
Signed-off-by: Evan Anderson <evan1124@gmail.com>
build: no longer build emulator by default

This is just increasing build times when most people are not using it.
Let's speed up builds a bit.

Building emulator should still be possible by appending BUILD_EMULATOR=true
to the build command

PS2: Let's keep the darwin warning.

Change-Id: Ibd8e2b90455bd603a691c7b95466068b6fae212a
Signed-off-by: Andrew Warfield <hiasant@gmail.com>

Conflicts:
	core/main.mk
build: Set ccache base to build top

This enables ccache sharing between different build tree paths.

Change-Id: I99636bdd2779a6ccf0649f027e35cf67df44b6ae
Don't set CCACHE_BASEDIR if its already set

 * enable use of shared ccache

Change-Id: Ic708a5d5169291d674b167aa2c87bf2c8adaafae