Add 'ndk_compat' to the 'includes' directive of the 'ndk_compat' target, so that targets that include this library can directly reference 'cpu-features.h' like they did with the legacy Android NDK library.
* add windows ssse3,sse4_1,sse4_2 detection for non avx path
* remove special WESTMERE case
* move windows conditional redefinition to separate header
* fix minor issues
Include paths should be specified through includes
rather than copts, so that they are handled correctly when
cpu_features is included in another project as an external repository.