Implement a kernel gzip I/O interface, and use it for compressed
userland core dumps.
It's kern_gzio.c, not kern_gzio2.c
Whitespace fixes.
Make compression level a parameter to kern_gz_init.
Remove an obsolete #include.
General cleanup.
Fix the !COMPRESS_USER_CORES build.
Get rid of the COMPRESS_USER_CORES option and replace it with the more
generic GZIO.
Merge branch '20141021-gzio-refactoring' into 20141106-kernel-dump-refactoring