Noticed by @bnoordhuis in https://github.com/joyent/node/pull/5991#discussion_r5575946

This is [1] applied ahead of time. Summary:

    OpenBSD doesn't have <ucontext.h>. ucontext_t lives in <signal.h>
    and is a typedef for struct sigcontext. There is no uc_mcontext.

[1] https://codereview.chromium.org/21705003/

It shouldn't ignore it!

There're two possibile cases, which should be handled properly:

1. Having a default `SNICallback` which is using contexts, added with
  `server.addContext(...)` routine
2. Having a custom `SNICallback`.

In first case we may want to opt-out setting `.onsniselect` method (and
thus save some CPU time), if there're no contexts added. But, if custom
`SNICallback` is used, `.onsniselect` should always be set, because
server contexts don't affect it.

Code cleanup, replace a few uses of reinterpret_cast<T*>(void_ptr) with
static_cast<T*>(void_ptr).

Update a few more `Local<T>::New(isolate, persistent)` call sites to
`PersistentToLocal(isolate, persistent)` - the latter has a fast path
for non-weak persistent references.

When doing `FreeEmpty`, `NodeBIO` skips pre-allocated `head_` buffer.
However this might lead to double-freeing buffers since in `~NodeBIO()`
we're starting deallocation from `head_` buffer.

Commit 78d90945 updated src/*.cc to use the version of PersistentToLocal
that takes a v8::Isolate* as its first argument. This commit removes
the non-isolate version.

There is no need for it and it's a tiny bit slower than the version of
PersistentToLocal() that takes a v8::Isolate* as its first argument.

Now that values are checks in JS, no need for them to be checked in C++.

* Numeric values passed to alloc were converted to int32, not uint32
  before the range check, which allows wrap around on ToUint32. This
  would cause massive malloc calls and v8 fatal errors.
* dispose would not check if value was an Object, causing segfault if a
  Primitive was passed.
* kMaxLength was not enumerable.

Build breakage accidentally introduced in 8e29ce9f during code cleanup.

HAVE_OPENSSL is always defined (as either 0 or 1) so use #if rather
than #ifdef.

Fixes #5979.

Fix test from 30701d6e.

And, if present and non-empty, don't invoke `resumeSession` callback.

fix #5872

It's forced to violate the build/include_order rule because it includes
a header file generated with ctrpp.exe that doesn't include perflib.h
itself.

These are not real problems, and they are so plenty that actual problems
are hidden from view.

Commit 847c6d98 adds a 'project headers before system headers' check
to cpplint. Update the files in src/ to make the linter pass again.

Change the build/include_order rule to match our preference:
project headers before system headers.

The rationale is that system headers before project headers makes it
easy to slip in bugs where a project header that requires a definition
from a system header, forgets to include the system header but still
compiles because the source files that include the project header
coincidentally include the system header too.

A good example is the size_t type. A project header file that needs the
definition of size_t should include stddef.h but forgetting to do so
will probably go unnoticed for a long time because almost every other
system header includes stddef.h (either directly or indirectly) and
almost every source file includes one or more system headers.

Ergo, project headers before system headers. It's a good thing.

The project has moved to Jenkins. The status image is no longer
needed and perpetually shows a failed build. Remove it.

Also, exclude some C-headers, machine generated headers and tweaked
sources from cpplint file list.

* Support C-style header guards (/* comments */)
* Support `class NODE_EXTERN something`
* Support `}  // extern "C"` closures
* Ignore header order
* Ignore `long/short` usage (because of OpenSSL's API)

To prevent all unnecessary calls to JS from MakeCallback, the remaining
two immediate return variables inTick and lastThrew have been added to
infoBox. Now MakeCallback should never need to call into JS unless it
absolutely has to.

Also removed Tock. Performance tests showed it was at least as fast or
faster than using a normal object, and this is more readable.

Don't throw an exception when the argument to %j is an object that
contains circular references, it's not helpful. Catch the exception
and return the string '[Circular]'.

Prior, strings would first be converted to a Buffer before being written
to disk. Now the intermediary step has been removed.

Other changes of note:

* Class member "must_free" was added to req_wrap so to track if the
  memory needs to be manually cleaned up after use.
* External String Resource support, so the memory will be used directly
  instead of copying out the data.
* Docs have been updated to reflect that if position is not a number
  then it will assume null. Previously it specified the argument must be
  null, but that was not how the code worked. An attempt was made to
  only support == null, but there were too many tests that assumed !=
  number would be enough.
* Docs update show some of the write/writeSync arguments are optional.

The method is useful elsewhere when needing to check if external and
grab data.

Non-release upgrade so pending patches can land.

* Use ARRAY_SIZE() rather than scanning until we hit a NULL entry.
* Fix `-fsigned-char -Wnarrowing` compiler warnings. Harmless but
  numerous and annoying.
* Static-ify the modp_group and mod_groups arrays.
* Const-ify the modp_groups array.

No functional changes, just some code tightening. Clean up some style
inconsistencies while we are here.

It imports the definition into every source file that includes
string_bytes.h, as evidenced by the build suddenly breaking left
and right because of missing Handle/Local/String/Value imports.

Conflicts:
	AUTHORS
	ChangeLog
	deps/uv/ChangeLog
	deps/uv/src/version.c
	deps/uv/src/win/fs.c
	src/node.cc
	src/node_crypto.cc
	src/node_os.cc
	src/node_version.h