[CMake] Fix install of Swift's copy of Clang headers.
[CMake] Fix install of Swift's copy of Clang headers.

This is a speculative fix for rdar://problem/23570075, as fallout from
e6bdcbcc. I fixed the build directory, but not the install components.

milseman/swift,jtbandes/swift,dduan/swift,IngmarStein/swift,hughbe/swift,khizkhiz/swift,benlangmuir/swift,aschwaighofer/swift,atrick/swift,swiftix/swift.old,cbrentharris/swift,swiftix/swift,OscarSwanros/swift,cbrentharris/swift,arvedviehweger/swift,sdulal/swift,glessard/swift,deyton/swift,zisko/swift,LeoShimonaka/swift,airspeedswift/swift,lorentey/swift,therealbnut/swift,allevato/swift,JaSpa/swift,emilstahl/swift,khizkhiz/swift,slavapestov/swift,jtbandes/swift,kperryua/swift,tinysun212/swift-windows,atrick/swift,cbrentharris/swift,Jnosh/swift,emilstahl/swift,tkremenek/swift,parkera/swift,roambotics/swift,devincoughlin/swift,kstaring/swift,dduan/swift,devincoughlin/swift,ken0nek/swift,benlangmuir/swift,shahmishal/swift,parkera/swift,russbishop/swift,ken0nek/swift,amraboelela/swift,hooman/swift,hooman/swift,shajrawi/swift,cbrentharris/swift,modocache/swift,karwa/swift,gregomni/swift,tinysun212/swift-windows,kentya6/swift,CodaFi/swift,SwiftAndroid/swift,devincoughlin/swift,hooman/swift,gmilos/swift,russbishop/swift,alblue/swift,gribozavr/swift,LeoShimonaka/swift,kstaring/swift,roambotics/swift,modocache/swift,LeoShimonaka/swift,SwiftAndroid/swift,shahmishal/swift,djwbrown/swift,jckarter/swift,kperryua/swift,manavgabhawala/swift,codestergit/swift,sschiau/swift,gottesmm/swift,slavapestov/swift,shajrawi/swift,ken0nek/swift,brentdax/swift,ahoppen/swift,modocache/swift,atrick/swift,russbishop/swift,jckarter/swift,Ivacker/swift,arvedviehweger/swift,bitjammer/swift,adrfer/swift,brentdax/swift,felix91gr/swift,MukeshKumarS/Swift,CodaFi/swift,allevato/swift,kusl/swift,jtbandes/swift,sschiau/swift,ben-ng/swift,natecook1000/swift,sdulal/swift,brentdax/swift,karwa/swift,danielmartin/swift,stephentyrone/swift,ben-ng/swift,manavgabhawala/swift,sschiau/swift,tkremenek/swift,felix91gr/swift,sschiau/swift,lorentey/swift,shajrawi/swift,deyton/swift,apple/swift,huonw/swift,zisko/swift,emilstahl/swift,gregomni/swift,gregomni/swift,return/swift,amraboelela/swift,SwiftAndroid/swift,amraboelela/swift,calebd/swift,LeoShimonaka/swift,MukeshKumarS/Swift,glessard/swift,frootloops/swift,nathawes/swift,jmgc/swift,russbishop/swift,stephentyrone/swift,KrishMunot/swift,manavgabhawala/swift,swiftix/swift,emilstahl/swift,zisko/swift,KrishMunot/swift,natecook1000/swift,parkera/swift,bitjammer/swift,aschwaighofer/swift,danielmartin/swift,MukeshKumarS/Swift,felix91gr/swift,huonw/swift,JaSpa/swift,bitjammer/swift,adrfer/swift,huonw/swift,gmilos/swift,jckarter/swift,sdulal/swift,SwiftAndroid/swift,Ivacker/swift,Jnosh/swift,airspeedswift/swift,swiftix/swift,amraboelela/swift,cbrentharris/swift,gmilos/swift,ben-ng/swift,shajrawi/swift,djwbrown/swift,khizkhiz/swift,felix91gr/swift,gribozavr/swift,gribozavr/swift,adrfer/swift,tinysun212/swift-windows,JaSpa/swift,xedin/swift,felix91gr/swift,mightydeveloper/swift,emilstahl/swift,rudkx/swift,shahmishal/swift,Jnosh/swift,gmilos/swift,djwbrown/swift,gottesmm/swift,rudkx/swift,karwa/swift,tjw/swift,karwa/swift,manavgabhawala/swift,alblue/swift,jmgc/swift,dduan/swift,jmgc/swift,natecook1000/swift,stephentyrone/swift,slavapestov/swift,jtbandes/swift,jmgc/swift,KrishMunot/swift,stephentyrone/swift,amraboelela/swift,benlangmuir/swift,kperryua/swift,nathawes/swift,tardieu/swift,russbishop/swift,tardieu/swift,SwiftAndroid/swift,cbrentharris/swift,xwu/swift,atrick/swift,MukeshKumarS/Swift,emilstahl/swift,felix91gr/swift,zisko/swift,aschwaighofer/swift,parkera/swift,practicalswift/swift,OscarSwanros/swift,JaSpa/swift,gribozavr/swift,jmgc/swift,frootloops/swift,codestergit/swift,tjw/swift,tardieu/swift,arvedviehweger/swift,ahoppen/swift,Jnosh/swift,huonw/swift,frootloops/swift,devincoughlin/swift,johnno1962d/swift,deyton/swift,OscarSwanros/swift,shajrawi/swift,return/swift,KrishMunot/swift,rudkx/swift,zisko/swift,swiftix/swift,jopamer/swift,swiftix/swift.old,austinzheng/swift,arvedviehweger/swift,slavapestov/swift,mightydeveloper/swift,tinysun212/swift-windows,harlanhaskins/swift,roambotics/swift,kusl/swift,lorentey/swift,jtbandes/swift,stephentyrone/swift,return/swift,gottesmm/swift,calebd/swift,khizkhiz/swift,austinzheng/swift,gregomni/swift,austinzheng/swift,OscarSwanros/swift,kstaring/swift,aschwaighofer/swift,mightydeveloper/swift,milseman/swift,JGiola/swift,Ivacker/swift,milseman/swift,tkremenek/swift,bitjammer/swift,gmilos/swift,adrfer/swift,mightydeveloper/swift,MukeshKumarS/Swift,Ivacker/swift,allevato/swift,russbishop/swift,manavgabhawala/swift,tkremenek/swift,glessard/swift,apple/swift,apple/swift,tkremenek/swift,rudkx/swift,khizkhiz/swift,dduan/swift,practicalswift/swift,stephentyrone/swift,johnno1962d/swift,shahmishal/swift,austinzheng/swift,JaSpa/swift,frootloops/swift,uasys/swift,hughbe/swift,shahmishal/swift,kstaring/swift,tjw/swift,therealbnut/swift,CodaFi/swift,dreamsxin/swift,glessard/swift,rudkx/swift,tinysun212/swift-windows,kentya6/swift,calebd/swift,sschiau/swift,natecook1000/swift,swiftix/swift.old,atrick/swift,johnno1962d/swift,khizkhiz/swift,gottesmm/swift,IngmarStein/swift,tardieu/swift,gregomni/swift,harlanhaskins/swift,frootloops/swift,benlangmuir/swift,tjw/swift,KrishMunot/swift,frootloops/swift,IngmarStein/swift,codestergit/swift,danielmartin/swift,nathawes/swift,kstaring/swift,practicalswift/swift,rudkx/swift,calebd/swift,nathawes/swift,mightydeveloper/swift,aschwaighofer/swift,xedin/swift,modocache/swift,gribozavr/swift,natecook1000/swift,natecook1000/swift,therealbnut/swift,gribozavr/swift,allevato/swift,OscarSwanros/swift,harlanhaskins/swift,swiftix/swift.old,jmgc/swift,practicalswift/swift,kentya6/swift,shajrawi/swift,brentdax/swift,hughbe/swift,lorentey/swift,bitjammer/swift,manavgabhawala/swift,kusl/swift,jckarter/swift,mightydeveloper/swift,Ivacker/swift,bitjammer/swift,sschiau/swift,practicalswift/swift,apple/swift,ben-ng/swift,calebd/swift,alblue/swift,cbrentharris/swift,KrishMunot/swift,sdulal/swift,alblue/swift,allevato/swift,JGiola/swift,gottesmm/swift,parkera/swift,brentdax/swift,practicalswift/swift,djwbrown/swift,devincoughlin/swift,modocache/swift,OscarSwanros/swift,roambotics/swift,kperryua/swift,Jnosh/swift,mightydeveloper/swift,emilstahl/swift,danielmartin/swift,shahmishal/swift,jopamer/swift,IngmarStein/swift,return/swift,benlangmuir/swift,Ivacker/swift,deyton/swift,xwu/swift,tardieu/swift,amraboelela/swift,xedin/swift,hughbe/swift,calebd/swift,johnno1962d/swift,ahoppen/swift,swiftix/swift.old,codestergit/swift,therealbnut/swift,zisko/swift,codestergit/swift,CodaFi/swift,therealbnut/swift,nathawes/swift,therealbnut/swift,parkera/swift,kusl/swift,benlangmuir/swift,nathawes/swift,CodaFi/swift,LeoShimonaka/swift,tinysun212/swift-windows,gribozavr/swift,adrfer/swift,gribozavr/swift,shajrawi/swift,jopamer/swift,lorentey/swift,djwbrown/swift,kentya6/swift,xedin/swift,gottesmm/swift,xwu/swift,codestergit/swift,tjw/swift,aschwaighofer/swift,ben-ng/swift,apple/swift,swiftix/swift,xwu/swift,brentdax/swift,karwa/swift,jckarter/swift,kstaring/swift,stephentyrone/swift,kusl/swift,arvedviehweger/swift,MukeshKumarS/Swift,shahmishal/swift,uasys/swift,OscarSwanros/swift,xwu/swift,kentya6/swift,ben-ng/swift,jopamer/swift,atrick/swift,cbrentharris/swift,manavgabhawala/swift,sschiau/swift,ben-ng/swift,hooman/swift,xedin/swift,xedin/swift,CodaFi/swift,alblue/swift,tardieu/swift,sdulal/swift,sdulal/swift,devincoughlin/swift,LeoShimonaka/swift,kusl/swift,hughbe/swift,kusl/swift,jmgc/swift,IngmarStein/swift,dduan/swift,roambotics/swift,hooman/swift,roambotics/swift,jtbandes/swift,djwbrown/swift,sdulal/swift,huonw/swift,uasys/swift,ken0nek/swift,uasys/swift,lorentey/swift,Ivacker/swift,xwu/swift,adrfer/swift,karwa/swift,JGiola/swift,airspeedswift/swift,alblue/swift,gmilos/swift,airspeedswift/swift,return/swift,JGiola/swift,amraboelela/swift,SwiftAndroid/swift,dduan/swift,bitjammer/swift,harlanhaskins/swift,ahoppen/swift,felix91gr/swift,gmilos/swift,JGiola/swift,apple/swift,airspeedswift/swift,MukeshKumarS/Swift,karwa/swift,danielmartin/swift,parkera/swift,uasys/swift,harlanhaskins/swift,lorentey/swift,austinzheng/swift,danielmartin/swift,jopamer/swift,slavapestov/swift,jckarter/swift,kusl/swift,deyton/swift,alblue/swift,uasys/swift,practicalswift/swift,xwu/swift,jopamer/swift,CodaFi/swift,hughbe/swift,aschwaighofer/swift,calebd/swift,Jnosh/swift,djwbrown/swift,karwa/swift,tjw/swift,ken0nek/swift,xedin/swift,ken0nek/swift,allevato/swift,milseman/swift,kentya6/swift,tjw/swift,JaSpa/swift,kperryua/swift,glessard/swift,harlanhaskins/swift,milseman/swift,hooman/swift,airspeedswift/swift,tardieu/swift,glessard/swift,uasys/swift,deyton/swift,sschiau/swift,khizkhiz/swift,parkera/swift,johnno1962d/swift,kperryua/swift,deyton/swift,hughbe/swift,IngmarStein/swift,swiftix/swift,gottesmm/swift,devincoughlin/swift,swiftix/swift,codestergit/swift,xedin/swift,dreamsxin/swift,tkremenek/swift,practicalswift/swift,JaSpa/swift,gregomni/swift,airspeedswift/swift,arvedviehweger/swift,johnno1962d/swift,tinysun212/swift-windows,jtbandes/swift,austinzheng/swift,brentdax/swift,allevato/swift,natecook1000/swift,Jnosh/swift,emilstahl/swift,modocache/swift,dduan/swift,milseman/swift,jopamer/swift,hooman/swift,tkremenek/swift,slavapestov/swift,IngmarStein/swift,therealbnut/swift,russbishop/swift,harlanhaskins/swift,milseman/swift,ken0nek/swift,return/swift,kstaring/swift,ahoppen/swift,huonw/swift,SwiftAndroid/swift,LeoShimonaka/swift,lorentey/swift,danielmartin/swift,huonw/swift,kperryua/swift,jckarter/swift,ahoppen/swift,swiftix/swift.old,shahmishal/swift,austinzheng/swift,shajrawi/swift,JGiola/swift,return/swift,swiftix/swift.old,sdulal/swift,arvedviehweger/swift,swiftix/swift.old,nathawes/swift,kentya6/swift,KrishMunot/swift,Ivacker/swift,slavapestov/swift,mightydeveloper/swift,kentya6/swift,devincoughlin/swift,LeoShimonaka/swift,zisko/swift,modocache/swift,frootloops/swift,johnno1962d/swift,adrfer/swift