Use swiftc in CMake's add_swift_executable, add_swift_library
Use swiftc in CMake's add_swift_executable, add_swift_library

So that the stdlib and benchmarks will build with swiftc.

Swift SVN r20477

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