Enable the passing of multiple extra flags via SWIFT_EXTRA_FLAGS.
Enable the passing of multiple extra flags via SWIFT_EXTRA_FLAGS.

By quoting the variable, cmake would assume that it was one item. This makes
sure it is treated as multiple items.

Swift SVN r14170

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