Convert from jemalloc's obsolete *allocm() to *allocx().

Summary: Convert from jemalloc's obsolete *allocm() to *allocx().

Strengthen goodMallocSize() to always return a jemalloc size class, so
that xallocx() success/failure detection is simple.

Reviewed By: @andralex

Differential Revision: D1535841
Add option for saying which nginx binary to use

Summary: Some packages don't install it into $PATH

refs facebook/hhvm#3664

Reviewed By: @ptarjan

Differential Revision: D1544870
Use EqX instead of Eq for Obj/Num comparisons.

Summary: Converting an Obj to Int or Dbl will reenter the VM to raise a notice.

Reviewed By: @jano

Differential Revision: D1542454
Update third-party
Improve process cleanup for OSS benchmarker

Summary: - HHVM attempts to shutdown via admin server first. Catch failures there, and fall back on killing the process
- Check that the streams are still valid before attempting to close them

refs facebook/hhvm#3664

Reviewed By: @JoelMarcey

Differential Revision: D1545273
Update cmake files to require jemalloc >= 3.5.1

Summary: @jasone landed a diff this morning which requires the allocx()
APIs in jemalloc.  Provide a useful error message if our version is
too old.

Reviewed By: @JoelMarcey

Differential Revision: D1545626
Add T_FINALLY to constants

Summary: Fixes #3703
Closes https://github.com/facebook/hhvm/pull/3708

Reviewed By: @sgolemon

Differential Revision: D1544682
make class closure consist with PHP

Summary: See #3431
Closes https://github.com/facebook/hhvm/pull/3460

Reviewed By: @sgolemon

Differential Revision: D1496023
Teach Hack about more curl constants

Reviewed By: @jwatzman

Differential Revision: D1541320
Refactor the parsing and processing of configuration options ... just a bit ...

Summary: ... and fix some bugs too :)

I was running into problems where it seemed like `-v` overrides were not being respected. So I wanted
to make sure that we had one goto place for parsing, processing and binding of configuration opens,
for easier debugging. This ended up into a bit of a refactor of our configuration option process.

Found a bug in `IniSetting::Set` where updates were not happening to existing pairs. This might
have been the biggest find during this whole process.

The second biggest find was probably the sort of subtle re-parsing of ini files for extension constants.
Right now we parse the whole file again; thus un-overriding any overrides that were given at the command
line. Needed to be a bit more clever on how we do this.

Reviewed By: @ptarjan

Differential Revision: D1524620