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>
Fix droiddoc generation.

We want javadoc generated from the standard libraries
we supply and not the host standard libraries.

This also has the side effect of fixing javadoc generation
for java7 APIs that android introduced, while compiling
with java6.

bug: 8992787
Change-Id: Idebc7e12c7743a43b425ef4971f4482719fd480d
build: Set ccache base to build top

This enables ccache sharing between different build tree paths.

Change-Id: I99636bdd2779a6ccf0649f027e35cf67df44b6ae
Build: support building with openjdk and java6

Change-Id: I4359f802722a7563ff9acbbc9f30b8f7499f4609