issue-628:package missing stacktrace_powerpc-{linux,darwin}-inl.h

This headers were missing in .tar.gz because they were not mentioned
anywhere in Makefile.am.
applied chromium patch fixing some build issue on android

This applies patch from: https://codereview.chromium.org/284843002/ by
jungjik.lee@samsung.com
updated NEWS for 2.2.1
bumped version to 2.2.1
issue-631: fixed miscompilation of debugallocation without mmap

This applies patch sent by user iamxujian.

Clearly, when I updated debugallocation to fix issue-464 I've broken
no-mmap path by forgetting closing brace.