Add Android cross-compilation support for x86

Add Android cross-compilation support for x86

TEST=make android-ia32.release

Obsoleted by https://chromiumcodereview.appspot.com/10778033/.

[Lijuan Xiao, 2012-05-11 04:08:25]

Hi, I saw v8 already support android cross-compilation for ARM. Here I submit a
patch to add the support for x86. Would you please help review? Many thanks.

[Yang, 2012-05-11 06:38:30]

Adding Jakob.

I haven't had a close look at the patch yet, but please do not use tabstops for
indentation and keep the 80-character limit per line.

[Jakob Kummerow, 2012-05-11 09:06:35]

Tabs in the Makefile are fine, as they're required by standard Makefile syntax.
Please use only one tab at the beginning of the line, then spaces as necessary
for additional indentation.

However, I don't like all the duplication this CL introduces. Can you refactor
the existing android.gypi so that it supports both ARM and x86 targets? Most of
the definitions are the same anyway, and the rest should be able to be
parameterized. Have a look at http://code.google.com/p/gyp/w/list to learn more
about how to put conditional stuff into GYP files.

My goal would be to have a single "android" make target that takes  a
"v8_target_arch" parameter to specify the architecture. Or something along those
lines.

I can have a stab at this myself, but that'd be at the end of next week at the
earliest. For this, it would be helpful if you could give me specific
instructions how to setup the toolchain for Android-x86 (which we should put
into the V8 wiki anyway once we have support for this). Is it simply
"make-standalone-toolchain.sh --arch=x86" and everything else is the same as for
ARM?

Another note: the entire build/android.gypi file is somewhat experimental. I'm
sure some of the definitions in there are not needed, and the overall structure
could probably be improved. I'd be interested in suggestions, if you have any.

[Lijuan Xiao, 2012-05-11 09:43:13]

Hi, Jakob, thanks for comments.

Yes, to setup toolchain for x86, we just need add --arch=x86 when executing
make-standalone-toolchain.sh. That's the only thing to add to the wiki.

When I made the patch, I also thought of use the unified android.gypi. However I
noticed there exist armu.gypi and mipsu.gypi (missing in latest version), and
thought developers can refine android-arm.gypi and android-ia32.gypi
respectively later. If you think this way is not acceptable, I could have a look
on how to combine them when available. Your try is also appreciated. Let us keep
tuned here.