Fix CMake warning

Summary: Latest CMake on OS X with brew surfaced this warning and that
this check was not doing what it was originally intended to do.
Removed legacy unused callbacks

Remove unused asio_set_on_{started,failed}_callback.

Reviewed By: alexsuhan

Differential Revision: D1016805
Rename ContinuationWaitHandle to AsyncFunctionWaitHandle

- rename ContinuationWaitHandle to AsyncFunctionWaitHandle
- rename onYield hook to onAwait hook

Reviewed By: @billf

Differential Revision: D1016901
introduce a helper for overwriting an ActRec as cells

... as discussed.

Reviewed By: @jdelong

Differential Revision: D1013186
Clean up shuffleArgs.

Use smart container, return the move schedule by value,
and do some manual CSE for clarity.

Reviewed By: @jdelong

Differential Revision: D1016082
Support custom reason for status header

Support custom reason for status header

Closes #967
Closes #1183

Reviewed By: afrind

Differential Revision: D1015633

Pulled By: @scannell
Better symbol resolution for pprof

Using names more in line with Func::prettyPrint and using full
names for builtins makes it a lot more clear what is going on.

Reviewed By: @hermanventer

Differential Revision: D1016225
Move function prologues out of tx64

This is the last big chunk of code emission logic in tx64. The path to
getting stuff working in ARM is now blocked by function prologues, so
this needs to happen now.

Function prologues are delicate and messy, so this change isn't 100%
straight code motion.

- The call-array prologue stuff was quite smooth, and all the changes
  are mechanical.

- funcPrologue() turned out to have a pretty big and easily separable
  chunk of x64-specific code in the middle, sandwiched between big
  chunks of platform-agnostic code. I pulled out the platform-specific
  part into the new module I created.

- All the function-guard smashing stuff is very platform-specific so got
  pulled out as well.

Reviewed By: @ottoni

Differential Revision: D1013868
Don't truncate HphpArray's allocation size to 32 bits

For arrays that hold ~150 million or more elements, we need to
allocate more than 4GB of ram. computeAllocBytes used to return a uint32_t so
we were truncating the real size and allocating a lot less memory than we
needed.

Reviewed By: @jdelong

Differential Revision: D1016732
Fixes for PGO mode

This fixes a couple of asserts I hit running www in DEBUG mode with
-vEval.JitPGO=1 -vEval.JitRegionSelector=hottrace
-vEval.JitPGOHotOnly=0.

Reviewed By: @ottoni

Differential Revision: D1016284
update .gitignore for HHVM

Adds a few more filetypes to the HHVM .gitignore

Reviewed By: @ptarjan

Differential Revision: D1015499

Pulled By: @scannell
Add the pull request that fixes the interface problem with Doctrine

The interface problem ended up being a problem with Dbal (a dependency). This was fixed via a fork from the main dbal repo, but hasn't been merged into the main repo yet.

The script is updated to support pull requests.

Reviewed By: @ptarjan

Differential Revision: D1017683
Add Pear and Magento to our test script

Pear and Magento now run correctly with unit testing. I had to do an additional download for PEAR via the new
pull request mechanism, but it works out well. Neither fatal! :)

Reviewed By: @ptarjan

Differential Revision: D1018560
Stub out two sqlite PDO methods.

Doctrine unit tests calls one of these two methods (sqliteCreateFunction). We fatal because we do not support it. The PHP docs says these functions are experimental, but let's not fatal if we don't have to.

http://www.php.net/manual/en/pdo.sqlitecreatefunction.php

With this diff (and a Doctrine patch that fixes some interface issues it was having), we no longer fatal in Doctrine! We do, however, fail a lot of tests.

Reviewed By: @ptarjan

Differential Revision: D1017386
Add support for emitting PC-relative loads to vixl assembler

The lower-level assembler infra is there, but this addressing mode
wasn't exposed in the public-facing API. This will allow us to generate
better code for stuff like smashable jumps, which I've included in this
diff. (Previously, it was one instruction to compute an address and
another one to load; now it's just a load.)

Reviewed By: @jdelong

Differential Revision: D1017834
Fix three eval() bugs

* @ eval() was not being silenced correctly
* If the string passed to eval() hits a parse error, then the runtime
  is not supposed to fatal. We currently do.
* Errors in eval() code did not print a valid file name, they now
  print it as "$FILENAME($LINE1) : eval()'d code on line $LINE2"

Closes #945

Reviewed By: @jdelong

Differential Revision: D1006603
Describe the global litstr table in bytecode.specification

Also spellchecked, because OCD

Reviewed By: @jdelong

Differential Revision: D1017649