[PR] Attempt to pass -ppx flag to ocamldep from ocp-build
[PR] Attempt to pass -ppx flag to ocamldep from ocp-build

Summary:
Our OSX travis ocp-builds were failing due to the flow-monitor library
having its source files compiled in the wrong order, even though it has
`sort=true`. This sounds like ocamldep failing to interpret ppx. This is
reinforced by the fact that our travis linux builds are passing and I
can't repro on my local OSX laptop.

I poked around the ocp-build source and found a dep option which seems
to pass flags through to ocamldep. I can confirm my local OSX build
still works. Let's see what travis thinks...
Closes https://github.com/facebook/flow/pull/5886

Reviewed By: nmote

Differential Revision: D7099541

Pulled By: gabelevi

fbshipit-source-id: 17938a46214cf927bae1285006c94a22c5dc9120

JonathanUsername/flow,gabelevi/flow,JonathanUsername/flow,facebook/flow,facebook/flow,gabelevi/flow,mroch/flow,nmote/flow,facebook/flow,samwgoldman/flow,mroch/flow,samwgoldman/flow,facebook/flow,jamesgpearce/flow,nmote/flow,gabelevi/flow,nmote/flow,mroch/flow,gabelevi/flow,JonathanUsername/flow,samwgoldman/flow,claudiopro/flow,claudiopro/flow,nmote/flow,AgentME/flow,mroch/flow,JonathanUsername/flow,popham/flow,JonathanUsername/flow,JonathanUsername/flow,samwgoldman/flow,nmote/flow,jamesgpearce/flow,facebook/flow,jamesgpearce/flow,facebook/flow,AgentME/flow,AgentME/flow,popham/flow,popham/flow,mroch/flow,AgentME/flow,popham/flow,samwgoldman/flow,gabelevi/flow,AgentME/flow,jamesgpearce/flow,facebook/flow,nmote/flow,samwgoldman/flow,jamesgpearce/flow,gabelevi/flow,popham/flow,samwgoldman/flow,claudiopro/flow,claudiopro/flow,mroch/flow,jamesgpearce/flow,mroch/flow,JonathanUsername/flow,gabelevi/flow,popham/flow,nmote/flow,claudiopro/flow,popham/flow,jamesgpearce/flow