Fix GCC 4.8 mingw build

Export CXX_FOR_BUILD otherwise the default g++ can have different
bitness than libiberty.a which is always built in 32-bit for now.
Didn't happen prior to GCC 4.8 because GCC was in C only.  GCC from
4.8 now uses C++ as its implementation language

Change-Id: I318a2e469e1f1ce5cea71654ca5387d26cee5b73
Add aarch64

Change-Id: I0575d428472c12b56e10367abb73a2b5fd794a08
Merge remote-tracking branch 'aosp/master' into HEAD
Update arm-androideabi script

Change-Id: I3ce546bf8658d1fc39b4f4175bdd980932afdf6e