Add missing header includes
Add missing header includes

Today we get these headers indirectly, but when compiling against
`llvm.org/master` the build breaks.

allevato/swift,hooman/swift,parkera/swift,apple/swift,glessard/swift,rudkx/swift,JGiola/swift,allevato/swift,xwu/swift,glessard/swift,xwu/swift,hooman/swift,airspeedswift/swift,apple/swift,tkremenek/swift,aschwaighofer/swift,jmgc/swift,hooman/swift,harlanhaskins/swift,stephentyrone/swift,xwu/swift,tkremenek/swift,atrick/swift,hooman/swift,hooman/swift,atrick/swift,nathawes/swift,harlanhaskins/swift,gregomni/swift,apple/swift,airspeedswift/swift,jckarter/swift,atrick/swift,benlangmuir/swift,gregomni/swift,stephentyrone/swift,jckarter/swift,xwu/swift,jmgc/swift,CodaFi/swift,jmgc/swift,CodaFi/swift,parkera/swift,parkera/swift,benlangmuir/swift,parkera/swift,rudkx/swift,roambotics/swift,ahoppen/swift,glessard/swift,ahoppen/swift,allevato/swift,benlangmuir/swift,harlanhaskins/swift,jckarter/swift,parkera/swift,aschwaighofer/swift,airspeedswift/swift,gregomni/swift,rudkx/swift,CodaFi/swift,apple/swift,ahoppen/swift,harlanhaskins/swift,parkera/swift,benlangmuir/swift,harlanhaskins/swift,airspeedswift/swift,roambotics/swift,xwu/swift,tkremenek/swift,apple/swift,allevato/swift,aschwaighofer/swift,tkremenek/swift,nathawes/swift,tkremenek/swift,glessard/swift,jckarter/swift,hooman/swift,roambotics/swift,atrick/swift,airspeedswift/swift,CodaFi/swift,roambotics/swift,airspeedswift/swift,CodaFi/swift,allevato/swift,aschwaighofer/swift,stephentyrone/swift,jckarter/swift,jmgc/swift,gregomni/swift,rudkx/swift,airspeedswift/swift,nathawes/swift,nathawes/swift,rudkx/swift,glessard/swift,allevato/swift,roambotics/swift,JGiola/swift,gregomni/swift,JGiola/swift,CodaFi/swift,apple/swift,jmgc/swift,roambotics/swift,JGiola/swift,xwu/swift,nathawes/swift,ahoppen/swift,tkremenek/swift,hooman/swift,jckarter/swift,nathawes/swift,nathawes/swift,parkera/swift,atrick/swift,JGiola/swift,gregomni/swift,parkera/swift,stephentyrone/swift,benlangmuir/swift,aschwaighofer/swift,xwu/swift,stephentyrone/swift,glessard/swift,benlangmuir/swift,JGiola/swift,ahoppen/swift,atrick/swift,harlanhaskins/swift,tkremenek/swift,stephentyrone/swift,CodaFi/swift,harlanhaskins/swift,allevato/swift,aschwaighofer/swift,jckarter/swift,jmgc/swift,rudkx/swift,jmgc/swift,stephentyrone/swift,ahoppen/swift,aschwaighofer/swift