Fix build-flow-debug Makefile target
Fix build-flow-debug Makefile target

Summary: Missing sedlex dep

Reviewed By: mroch

Differential Revision: D5248108

fbshipit-source-id: 486c2a1442a85ff56f541e0553228fbc4be191d8

TiddoLangerak/flow,MichaelDeBoey/flow,jamesgpearce/flow,mroch/flow,mroch/flow,gabelevi/flow,samwgoldman/flow,mroch/flow,popham/flow,TiddoLangerak/flow,ylu1317/flow,ylu1317/flow,ylu1317/flow,gabelevi/flow,claudiopro/flow,AgentME/flow,JonathanUsername/flow,samwgoldman/flow,TiddoLangerak/flow,mroch/flow,gabelevi/flow,mroch/flow,JonathanUsername/flow,MichaelDeBoey/flow,jamesgpearce/flow,jamesgpearce/flow,claudiopro/flow,samwgoldman/flow,nmote/flow,popham/flow,JonathanUsername/flow,claudiopro/flow,facebook/flow,nmote/flow,facebook/flow,claudiopro/flow,JonathanUsername/flow,claudiopro/flow,AgentME/flow,MichaelDeBoey/flow,samwgoldman/flow,facebook/flow,popham/flow,TiddoLangerak/flow,samwgoldman/flow,popham/flow,MichaelDeBoey/flow,samwgoldman/flow,jamesgpearce/flow,gabelevi/flow,TiddoLangerak/flow,MichaelDeBoey/flow,jamesgpearce/flow,facebook/flow,gabelevi/flow,facebook/flow,popham/flow,AgentME/flow,nmote/flow,gabelevi/flow,JonathanUsername/flow,jamesgpearce/flow,gabelevi/flow,nmote/flow,ylu1317/flow,JonathanUsername/flow,jamesgpearce/flow,AgentME/flow,AgentME/flow,popham/flow,mroch/flow,facebook/flow,ylu1317/flow,nmote/flow,nmote/flow,JonathanUsername/flow,nmote/flow,facebook/flow,mroch/flow,samwgoldman/flow,popham/flow