runtime: avoid some pedantic warnings from CPP (NFC)
runtime: avoid some pedantic warnings from CPP (NFC)

Expansion of undefined macros is 0.  This results in warnings when
building the runtime on Windows.  Ensure that the macros are defined
when checking the conditions.  NFC.

aschwaighofer/swift,tkremenek/swift,ahoppen/swift,allevato/swift,amraboelela/swift,tkremenek/swift,jopamer/swift,karwa/swift,stephentyrone/swift,rudkx/swift,xwu/swift,stephentyrone/swift,xedin/swift,jckarter/swift,parkera/swift,austinzheng/swift,amraboelela/swift,allevato/swift,gribozavr/swift,sschiau/swift,atrick/swift,austinzheng/swift,jmgc/swift,austinzheng/swift,nathawes/swift,tkremenek/swift,tjw/swift,jopamer/swift,shahmishal/swift,amraboelela/swift,devincoughlin/swift,atrick/swift,shajrawi/swift,xwu/swift,jckarter/swift,brentdax/swift,gribozavr/swift,allevato/swift,sschiau/swift,shajrawi/swift,brentdax/swift,roambotics/swift,brentdax/swift,allevato/swift,roambotics/swift,benlangmuir/swift,danielmartin/swift,austinzheng/swift,ahoppen/swift,allevato/swift,xedin/swift,glessard/swift,aschwaighofer/swift,sschiau/swift,JGiola/swift,apple/swift,tjw/swift,amraboelela/swift,huonw/swift,rudkx/swift,JGiola/swift,apple/swift,natecook1000/swift,xedin/swift,glessard/swift,atrick/swift,tjw/swift,JGiola/swift,jopamer/swift,karwa/swift,nathawes/swift,sschiau/swift,jckarter/swift,jmgc/swift,amraboelela/swift,xwu/swift,sschiau/swift,CodaFi/swift,xedin/swift,apple/swift,natecook1000/swift,harlanhaskins/swift,harlanhaskins/swift,glessard/swift,gregomni/swift,hooman/swift,jmgc/swift,shahmishal/swift,tjw/swift,glessard/swift,sschiau/swift,natecook1000/swift,tjw/swift,gribozavr/swift,aschwaighofer/swift,xwu/swift,devincoughlin/swift,jopamer/swift,tkremenek/swift,atrick/swift,shajrawi/swift,benlangmuir/swift,atrick/swift,brentdax/swift,karwa/swift,stephentyrone/swift,jckarter/swift,airspeedswift/swift,benlangmuir/swift,jmgc/swift,hooman/swift,harlanhaskins/swift,roambotics/swift,rudkx/swift,airspeedswift/swift,alblue/swift,airspeedswift/swift,gribozavr/swift,stephentyrone/swift,amraboelela/swift,alblue/swift,jckarter/swift,austinzheng/swift,CodaFi/swift,sschiau/swift,natecook1000/swift,lorentey/swift,nathawes/swift,benlangmuir/swift,rudkx/swift,gribozavr/swift,parkera/swift,lorentey/swift,allevato/swift,tkremenek/swift,CodaFi/swift,practicalswift/swift,brentdax/swift,devincoughlin/swift,huonw/swift,jmgc/swift,parkera/swift,practicalswift/swift,airspeedswift/swift,lorentey/swift,devincoughlin/swift,jckarter/swift,harlanhaskins/swift,xwu/swift,danielmartin/swift,roambotics/swift,lorentey/swift,devincoughlin/swift,CodaFi/swift,practicalswift/swift,apple/swift,aschwaighofer/swift,xedin/swift,lorentey/swift,xedin/swift,shahmishal/swift,JGiola/swift,aschwaighofer/swift,gregomni/swift,hooman/swift,danielmartin/swift,nathawes/swift,huonw/swift,danielmartin/swift,shajrawi/swift,devincoughlin/swift,parkera/swift,danielmartin/swift,danielmartin/swift,jopamer/swift,glessard/swift,karwa/swift,lorentey/swift,tjw/swift,shahmishal/swift,danielmartin/swift,xedin/swift,ahoppen/swift,alblue/swift,alblue/swift,parkera/swift,shajrawi/swift,hooman/swift,huonw/swift,shajrawi/swift,airspeedswift/swift,hooman/swift,stephentyrone/swift,devincoughlin/swift,benlangmuir/swift,shahmishal/swift,nathawes/swift,parkera/swift,gribozavr/swift,austinzheng/swift,practicalswift/swift,harlanhaskins/swift,benlangmuir/swift,nathawes/swift,alblue/swift,xwu/swift,stephentyrone/swift,practicalswift/swift,xedin/swift,parkera/swift,xwu/swift,karwa/swift,apple/swift,stephentyrone/swift,hooman/swift,karwa/swift,gribozavr/swift,huonw/swift,huonw/swift,rudkx/swift,ahoppen/swift,jopamer/swift,amraboelela/swift,karwa/swift,nathawes/swift,shahmishal/swift,ahoppen/swift,glessard/swift,shahmishal/swift,rudkx/swift,CodaFi/swift,tjw/swift,shahmishal/swift,airspeedswift/swift,hooman/swift,lorentey/swift,JGiola/swift,CodaFi/swift,gregomni/swift,gribozavr/swift,natecook1000/swift,jopamer/swift,natecook1000/swift,apple/swift,alblue/swift,atrick/swift,alblue/swift,allevato/swift,tkremenek/swift,aschwaighofer/swift,roambotics/swift,ahoppen/swift,harlanhaskins/swift,gregomni/swift,aschwaighofer/swift,practicalswift/swift,jmgc/swift,sschiau/swift,huonw/swift,CodaFi/swift,roambotics/swift,JGiola/swift,parkera/swift,gregomni/swift,practicalswift/swift,brentdax/swift,karwa/swift,jckarter/swift,lorentey/swift,jmgc/swift,gregomni/swift,devincoughlin/swift,practicalswift/swift,shajrawi/swift,austinzheng/swift,harlanhaskins/swift,tkremenek/swift,brentdax/swift,airspeedswift/swift,natecook1000/swift,shajrawi/swift