unix: avoid extra read, short-circuit on POLLHUP

Avoid going through an extra alloc_cb -> read() -> read_cb cycle when
the POLLHUP flag is set because we know the next read() will hit EOF.

Fixes #803.
include: remove lame comment from uv.h
test: don't use S_IREAD and S_IWRITE

They're BSD-isms and obsolete ones at that. Replace with S_IRUSR and
S_IWUSR. Alias as _S_IREAD and _S_IWRITE on Windows because the '90s
never ended in Redmond, WA.
uv: support android libuv standalone build

Tested most of my compilation in the previous patch on NodeJS
and extracted the patches from there. This patch ensures libuv
will be capable of building standalone as well, both with gyp
and Makefiles.

Build documentation was added to the README.md file.

Some tests are failing, and I have not heavily investigated
the reasons. The failures are generally on errors, and are
likely related to differences between fully POSIX-compatible
systems and android.
build: fix build breakage from 3fdd2a1

Make sure the android_build variable is defined.
src: make queue.h c++ compatible

Squelch a warning about a cast from void* to another pointer type.
It's legal C but not legal C++. Makes queue.h usable in node.js.
unix: s/ngx-queue.h/queue.h/ in checksparse.sh
2013.06.05, Version 0.10.10 (Stable)

Changes since version 0.10.9:

* include: document uv_update_time() and uv_now() (Ben Noordhuis)

* linux: fix cpu model parsing on newer arm kernels (Ben Noordhuis)

* linux: fix memory leak in uv_cpu_info() error path (Ben Noordhuis)

* linux: don't ignore OOM errors in uv_cpu_info() (Ben Noordhuis)

* unix, windows: move uv_now() to uv-common.c (Ben Noordhuis)

* darwin: make uv_fs_sendfile() respect length param (Wynn Wilkes)
Now working on v0.10.11
unix: unconditionally stop handle on close

Make sure the handle is fully stopped by the time uv__stream_close()
calls uv_read_stop(). Fixes the following assertion:

    Assertion failed: (!uv__io_active(&stream->io_watcher, UV__POLLOUT)
    || !ngx_queue_empty(&stream->write_completed_queue)
    || !ngx_queue_empty(&stream->write_queue)
    || stream->shutdown_req != NULL
    || stream->connect_req != NULL), function uv_read_stop,
    file ../deps/uv/src/unix/stream.c, line 1329.

Fixes joyent/node#5622.
freebsd: don't enable dtrace if it's not available
Merge remote-tracking branch 'origin/v0.10'

Conflicts:
	AUTHORS
	ChangeLog
	src/unix/stream.c
	src/version.c
unix: remove unused function uv_fatal_error()
unix, windows: clean up uv_thread_create()

Make uv_thread_create() and its helper function a little more DRY and
a little less impenetrable.
build: make HAVE_DTRACE=0 should disable dtrace
unix: remove overzealous assert

Several node.js users are hitting this assert under what appear to be
mostly benign conditions. In other words, it's unclear whether it's
catching real bugs or just has wrong expectations.

An aborting process is rather disruptive so I'm removing the assert
from the stable branch and relanding it in the master branch.
unix: clear UV_STREAM_SHUTTING after shutdown()

Fix a state machine buglet where the UV_STREAM_SHUTTING flag didn't get
cleared.
unix: fix busy loop, write if POLLERR or POLLHUP

This fixes a busy loop by working around a quirk with Linux kernels
<= 2.6.32 where an EPIPE or ECONNRESET error on a file descriptor that
is polled for EPOLLOUT but not EPOLLIN gets reported by epoll_wait() as
just EPOLLERR|EPOLLHUP, like this:

  epoll_wait(5, {{EPOLLERR|EPOLLHUP, {u32=12, u64=12}}}, 1024, 433) = 1

Before this commit, libuv called uv__read() which attempts to read from
the file descriptor.  With newer kernels and on other operating systems
that fails like this:

  read(12, "", 65536)         = -1 EPIPE (Broken pipe)

Which tells libuv there is a connection error and it should notify the
user of that.  On the affected Linux kernels however, the read succeeds
with an EOF:

  read(12, "", 65536)         = 0

Which is subsequently passed on to the user. In most cases, the user
will close the handle and everything is fine.

Node.js however sometimes keeps the handle open in an attempt to flush
pending write requests.  While libuv doesn't officially support this,
unofficially it works...

...except on those older kernels.  Because the kernel keeps waking up
the event loop without setting POLLOUT and because the read calls EOF
but don't error, libuv's I/O state machine doesn't progress.

That's why this commit changes uv__stream_io() to also write pending
data.  While the read() system call doesn't error, the write() system
call will.

Fixes joyent/node#5504.
2013.06.13, Version 0.10.11 (Stable)

Changes since version 0.10.10:

* unix: unconditionally stop handle on close (Ben Noordhuis)

* freebsd: don't enable dtrace if it's not available (Brian White)

* build: make HAVE_DTRACE=0 should disable dtrace (Timothy J. Fontaine)

* unix: remove overzealous assert (Ben Noordhuis)

* unix: clear UV_STREAM_SHUTTING after shutdown() (Ben Noordhuis)

* unix: fix busy loop, write if POLLERR or POLLHUP (Ben Noordhuis)
Now working on v0.10.12