code_env: do not use prctl on non-linux

get_process_name is platform specific. Check for Linux prctl function and
headers, and add reference to the relevant OSX function.

Signed-off-by: Noah Watkins <noahwatkins@gmail.com>
blkdev: support blkdev size query on osx

Support OSX, add checks for platform specific headers.

Signed-off-by: Noah Watkins <noahwatkins@gmail.com>
utime: use to_timespec for conversion

Signed-off-by: Noah Watkins <noahwatkins@gmail.com>
wbthrottle: use posix_fadvise if available

Only adding information about data usage. This won't effect correctness;
finding analagous techniques on other platforms woudld be useful for
performance.

Signed-off-by: Noah Watkins <noahwatkins@gmail.com>
context: handle platform without sem_timedwait

On OSX sem_timedwait is not available. This patch simply turns off the
heartbeat interval feature. Building a replacement should be possible, but is
needs some careful thought because pthread mutex/conds aren't thread safe, and
sem_post is called from SIGHUP.

Signed-off-by: Noah Watkins <noahwatkins@gmail.com>
mon: check for platform specific headers

Signed-off-by: Noah Watkins <noahwatkins@gmail.com>
doc: add osx build documentation

Signed-off-by: Noah Watkins <noahwatkins@gmail.com>
pipe: use feature tests for pipe2 and O_CLOEXEC

Signed-off-by: Noah Watkins <noahwatkins@gmail.com>
xattr: test for xattr routine variants

Signed-off-by: Noah Watkins <noahwatkins@gmail.com>
xattr: format code, remove unused intialization

Signed-off-by: Noah Watkins <noahwatkins@gmail.com>
fuse

fuse: better fuse check and compiler error fixes

Use pkg-config to look for libfuse (which also catches fuse4x on OSX).
This also fixes the HAVE_FUSE_GETGROUPS feature test, which hadn't been
updating LIBS prior to the test. This enabled code with an error in
fuse_ll.cc that had compiler errors.

Signed-off-by: Noah Watkins <noahwatkins@gmail.com>