Replaced the range decoder optimization that used arithmetic right shift with as fast version that doesn't need arithmetic right shift. Removed the related check from configure.ac.
Replaced the range decoder optimization that used arithmetic
right shift with as fast version that doesn't need
arithmetic right shift. Removed the related check from
configure.ac.

pombreda/go-liblzma,pombreda/go-liblzma,pombreda/go-liblzma