Enable building of gtest for Windows
Enable building of gtest for Windows

Windows does not have pthread support, and by defining the
GTEST_OS_WINDOWS flag, pthread support will not be built into
the windows version of gtest.

Change-Id: I0571fc52e77bb04175470d5750a7e2f46cdd5e86

xorware/android_build,xorware/android_build,xorware/android_build,xorware/android_build,xorware/android_build