Cover third version of freetype include

Summary: On Homebrew, we want

  #include <freetyp2/config/ftheader.h>

Because... Freetype.

Extend CMake/FindFreetype.cmake to check all three places
and set defines accordingly, then use those defines to
include the correct header.

Reviewed By: @ptarjan

Differential Revision: D1504378
Remove use of non-threadsafe strtok()

Summary: Interrestingly, someone decided to use strtok_r() because
the inner call to strtok() would collide.

That's true, of course, but they didn't seem to consider that
strtok() would also collide with any other strtok() in the
same process which might be running at the same time.

For instance, another request in another thread running the same
PHP script.

Let's just go ahead and make both loops be threadsafe, shall we?

Reviewed By: @ptarjan

Differential Revision: D1504531
remove duplicate json test dir

Summary: We had slow/ext_json and slow/json. Keep everything in ext_json
Closes #3471

Reviewed By: @JoelMarcey

Differential Revision: D1501008