build: make building with VS2017 15.8+ work again
build: make building with VS2017 15.8+ work again

This causes an ABI break on VS2017, but it is acceptable as there is no
guaranteed stability.

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