Runtime: conditional fallback to pthreads given we don't ship with the OS
Runtime: conditional fallback to pthreads given we don't ship with the OS

<rdar://problem/15169581> Custom allocation cache cannot assume OS implementation details for 1.0

Swift SVN r16842

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