build: correct flags for Windows build
build: correct flags for Windows build

Adjust the preprocessor macros to get correct DLL Storage for imported
functions.  This should help identify cases of incorrect linkage to
msvcrt/ucrt.

apple/swift,xedin/swift,jmgc/swift,xwu/swift,harlanhaskins/swift,glessard/swift,roambotics/swift,hooman/swift,harlanhaskins/swift,allevato/swift,parkera/swift,stephentyrone/swift,shahmishal/swift,jckarter/swift,allevato/swift,apple/swift,parkera/swift,apple/swift,roambotics/swift,ahoppen/swift,glessard/swift,CodaFi/swift,rudkx/swift,karwa/swift,apple/swift,shajrawi/swift,ahoppen/swift,ahoppen/swift,allevato/swift,airspeedswift/swift,sschiau/swift,parkera/swift,stephentyrone/swift,hooman/swift,gregomni/swift,gribozavr/swift,lorentey/swift,nathawes/swift,apple/swift,glessard/swift,shahmishal/swift,atrick/swift,tkremenek/swift,xedin/swift,roambotics/swift,gribozavr/swift,hooman/swift,devincoughlin/swift,sschiau/swift,lorentey/swift,rudkx/swift,karwa/swift,airspeedswift/swift,sschiau/swift,jmgc/swift,aschwaighofer/swift,CodaFi/swift,aschwaighofer/swift,tkremenek/swift,gribozavr/swift,glessard/swift,devincoughlin/swift,atrick/swift,devincoughlin/swift,shajrawi/swift,harlanhaskins/swift,JGiola/swift,stephentyrone/swift,parkera/swift,xwu/swift,lorentey/swift,stephentyrone/swift,allevato/swift,gregomni/swift,xedin/swift,roambotics/swift,allevato/swift,aschwaighofer/swift,ahoppen/swift,tkremenek/swift,xedin/swift,gregomni/swift,airspeedswift/swift,jmgc/swift,JGiola/swift,atrick/swift,hooman/swift,benlangmuir/swift,CodaFi/swift,xwu/swift,gribozavr/swift,jckarter/swift,karwa/swift,JGiola/swift,shahmishal/swift,rudkx/swift,gregomni/swift,xedin/swift,JGiola/swift,airspeedswift/swift,harlanhaskins/swift,atrick/swift,benlangmuir/swift,shajrawi/swift,gregomni/swift,xedin/swift,benlangmuir/swift,stephentyrone/swift,rudkx/swift,rudkx/swift,harlanhaskins/swift,parkera/swift,karwa/swift,devincoughlin/swift,nathawes/swift,karwa/swift,shahmishal/swift,xwu/swift,jmgc/swift,devincoughlin/swift,atrick/swift,stephentyrone/swift,shahmishal/swift,atrick/swift,aschwaighofer/swift,parkera/swift,stephentyrone/swift,sschiau/swift,apple/swift,glessard/swift,nathawes/swift,JGiola/swift,glessard/swift,parkera/swift,nathawes/swift,shahmishal/swift,allevato/swift,harlanhaskins/swift,sschiau/swift,hooman/swift,benlangmuir/swift,shahmishal/swift,airspeedswift/swift,sschiau/swift,karwa/swift,aschwaighofer/swift,gribozavr/swift,sschiau/swift,xwu/swift,lorentey/swift,tkremenek/swift,tkremenek/swift,roambotics/swift,lorentey/swift,shajrawi/swift,xedin/swift,xedin/swift,lorentey/swift,hooman/swift,benlangmuir/swift,shajrawi/swift,CodaFi/swift,tkremenek/swift,CodaFi/swift,tkremenek/swift,jckarter/swift,hooman/swift,aschwaighofer/swift,jmgc/swift,jmgc/swift,jckarter/swift,karwa/swift,karwa/swift,devincoughlin/swift,lorentey/swift,devincoughlin/swift,jckarter/swift,benlangmuir/swift,gribozavr/swift,gribozavr/swift,rudkx/swift,shajrawi/swift,lorentey/swift,gribozavr/swift,xwu/swift,shahmishal/swift,nathawes/swift,CodaFi/swift,aschwaighofer/swift,devincoughlin/swift,parkera/swift,JGiola/swift,airspeedswift/swift,CodaFi/swift,jmgc/swift,nathawes/swift,xwu/swift,allevato/swift,nathawes/swift,jckarter/swift,shajrawi/swift,ahoppen/swift,ahoppen/swift,shajrawi/swift,airspeedswift/swift,gregomni/swift,roambotics/swift,harlanhaskins/swift,sschiau/swift,jckarter/swift