[CMake] Use precondition in _add_swift_lipo_target
[CMake] Use precondition in _add_swift_lipo_target

Use the `precondition` CMake function added in e12fff76fd, rather than
custom logic, to check if arguments to `_add_swift_lipo_target` are not
set.

shahmishal/swift,gottesmm/swift,nathawes/swift,ahoppen/swift,arvedviehweger/swift,gregomni/swift,rudkx/swift,swiftix/swift,gottesmm/swift,kperryua/swift,djwbrown/swift,ben-ng/swift,sschiau/swift,nathawes/swift,harlanhaskins/swift,hughbe/swift,gregomni/swift,amraboelela/swift,milseman/swift,alblue/swift,felix91gr/swift,tkremenek/swift,jtbandes/swift,austinzheng/swift,nathawes/swift,ben-ng/swift,huonw/swift,roambotics/swift,djwbrown/swift,harlanhaskins/swift,alblue/swift,brentdax/swift,gottesmm/swift,gmilos/swift,calebd/swift,huonw/swift,harlanhaskins/swift,tkremenek/swift,uasys/swift,xwu/swift,hughbe/swift,hughbe/swift,jopamer/swift,JaSpa/swift,gregomni/swift,JGiola/swift,gmilos/swift,milseman/swift,kstaring/swift,zisko/swift,gribozavr/swift,xedin/swift,zisko/swift,jtbandes/swift,atrick/swift,calebd/swift,milseman/swift,xwu/swift,danielmartin/swift,gmilos/swift,danielmartin/swift,codestergit/swift,therealbnut/swift,roambotics/swift,hooman/swift,parkera/swift,gmilos/swift,xwu/swift,swiftix/swift,deyton/swift,CodaFi/swift,hooman/swift,CodaFi/swift,shajrawi/swift,xedin/swift,natecook1000/swift,gottesmm/swift,austinzheng/swift,frootloops/swift,kstaring/swift,kstaring/swift,JaSpa/swift,kstaring/swift,hooman/swift,austinzheng/swift,apple/swift,milseman/swift,aschwaighofer/swift,zisko/swift,JGiola/swift,djwbrown/swift,devincoughlin/swift,deyton/swift,tkremenek/swift,hughbe/swift,calebd/swift,roambotics/swift,apple/swift,OscarSwanros/swift,practicalswift/swift,karwa/swift,uasys/swift,jopamer/swift,lorentey/swift,CodaFi/swift,tjw/swift,arvedviehweger/swift,kperryua/swift,glessard/swift,tardieu/swift,shahmishal/swift,swiftix/swift,bitjammer/swift,gribozavr/swift,jmgc/swift,practicalswift/swift,tjw/swift,practicalswift/swift,sschiau/swift,karwa/swift,OscarSwanros/swift,xedin/swift,benlangmuir/swift,modocache/swift,bitjammer/swift,tjw/swift,OscarSwanros/swift,arvedviehweger/swift,felix91gr/swift,tjw/swift,CodaFi/swift,tardieu/swift,sschiau/swift,shahmishal/swift,xedin/swift,ben-ng/swift,danielmartin/swift,hughbe/swift,shajrawi/swift,stephentyrone/swift,modocache/swift,modocache/swift,stephentyrone/swift,jmgc/swift,tinysun212/swift-windows,gottesmm/swift,tinysun212/swift-windows,karwa/swift,felix91gr/swift,arvedviehweger/swift,alblue/swift,kstaring/swift,benlangmuir/swift,huonw/swift,gmilos/swift,ahoppen/swift,benlangmuir/swift,austinzheng/swift,huonw/swift,kperryua/swift,gmilos/swift,gmilos/swift,arvedviehweger/swift,jopamer/swift,tkremenek/swift,milseman/swift,jmgc/swift,jckarter/swift,deyton/swift,aschwaighofer/swift,JGiola/swift,frootloops/swift,lorentey/swift,harlanhaskins/swift,glessard/swift,huonw/swift,gribozavr/swift,atrick/swift,hughbe/swift,aschwaighofer/swift,tardieu/swift,Jnosh/swift,devincoughlin/swift,lorentey/swift,return/swift,tjw/swift,xwu/swift,return/swift,uasys/swift,danielmartin/swift,CodaFi/swift,brentdax/swift,Jnosh/swift,OscarSwanros/swift,parkera/swift,ben-ng/swift,amraboelela/swift,allevato/swift,therealbnut/swift,lorentey/swift,alblue/swift,allevato/swift,therealbnut/swift,tinysun212/swift-windows,manavgabhawala/swift,stephentyrone/swift,jmgc/swift,karwa/swift,amraboelela/swift,tkremenek/swift,austinzheng/swift,deyton/swift,codestergit/swift,devincoughlin/swift,jckarter/swift,jckarter/swift,allevato/swift,Jnosh/swift,ahoppen/swift,kstaring/swift,xedin/swift,austinzheng/swift,xwu/swift,sschiau/swift,codestergit/swift,shajrawi/swift,felix91gr/swift,ahoppen/swift,jtbandes/swift,sschiau/swift,jckarter/swift,lorentey/swift,allevato/swift,gribozavr/swift,deyton/swift,jmgc/swift,alblue/swift,benlangmuir/swift,JGiola/swift,jopamer/swift,karwa/swift,lorentey/swift,parkera/swift,Jnosh/swift,codestergit/swift,return/swift,swiftix/swift,codestergit/swift,calebd/swift,apple/swift,gribozavr/swift,shajrawi/swift,jtbandes/swift,parkera/swift,zisko/swift,danielmartin/swift,JaSpa/swift,manavgabhawala/swift,return/swift,jckarter/swift,sschiau/swift,shahmishal/swift,allevato/swift,shahmishal/swift,brentdax/swift,JaSpa/swift,milseman/swift,atrick/swift,manavgabhawala/swift,benlangmuir/swift,rudkx/swift,codestergit/swift,gribozavr/swift,tinysun212/swift-windows,zisko/swift,jtbandes/swift,frootloops/swift,harlanhaskins/swift,Jnosh/swift,ben-ng/swift,austinzheng/swift,jtbandes/swift,practicalswift/swift,deyton/swift,bitjammer/swift,lorentey/swift,airspeedswift/swift,danielmartin/swift,ahoppen/swift,airspeedswift/swift,rudkx/swift,glessard/swift,JaSpa/swift,gottesmm/swift,modocache/swift,frootloops/swift,glessard/swift,uasys/swift,gribozavr/swift,shahmishal/swift,glessard/swift,arvedviehweger/swift,rudkx/swift,therealbnut/swift,JGiola/swift,amraboelela/swift,shajrawi/swift,devincoughlin/swift,alblue/swift,OscarSwanros/swift,amraboelela/swift,gregomni/swift,nathawes/swift,apple/swift,tardieu/swift,manavgabhawala/swift,return/swift,kperryua/swift,calebd/swift,kperryua/swift,natecook1000/swift,brentdax/swift,brentdax/swift,parkera/swift,harlanhaskins/swift,hughbe/swift,devincoughlin/swift,kperryua/swift,bitjammer/swift,tjw/swift,xedin/swift,swiftix/swift,sschiau/swift,manavgabhawala/swift,airspeedswift/swift,apple/swift,alblue/swift,CodaFi/swift,gregomni/swift,karwa/swift,practicalswift/swift,hooman/swift,atrick/swift,devincoughlin/swift,tkremenek/swift,CodaFi/swift,gottesmm/swift,Jnosh/swift,natecook1000/swift,kstaring/swift,jckarter/swift,JaSpa/swift,tinysun212/swift-windows,arvedviehweger/swift,uasys/swift,shahmishal/swift,aschwaighofer/swift,stephentyrone/swift,bitjammer/swift,natecook1000/swift,xedin/swift,shahmishal/swift,jopamer/swift,jckarter/swift,djwbrown/swift,return/swift,airspeedswift/swift,tjw/swift,xwu/swift,manavgabhawala/swift,felix91gr/swift,therealbnut/swift,return/swift,hooman/swift,allevato/swift,practicalswift/swift,frootloops/swift,practicalswift/swift,bitjammer/swift,parkera/swift,tardieu/swift,airspeedswift/swift,jopamer/swift,kperryua/swift,ben-ng/swift,harlanhaskins/swift,Jnosh/swift,benlangmuir/swift,natecook1000/swift,therealbnut/swift,hooman/swift,aschwaighofer/swift,amraboelela/swift,gribozavr/swift,modocache/swift,nathawes/swift,brentdax/swift,devincoughlin/swift,gregomni/swift,nathawes/swift,frootloops/swift,huonw/swift,karwa/swift,felix91gr/swift,brentdax/swift,OscarSwanros/swift,aschwaighofer/swift,codestergit/swift,modocache/swift,natecook1000/swift,tardieu/swift,djwbrown/swift,lorentey/swift,shajrawi/swift,uasys/swift,OscarSwanros/swift,felix91gr/swift,aschwaighofer/swift,parkera/swift,jopamer/swift,tkremenek/swift,modocache/swift,djwbrown/swift,natecook1000/swift,airspeedswift/swift,tinysun212/swift-windows,amraboelela/swift,JaSpa/swift,apple/swift,therealbnut/swift,karwa/swift,allevato/swift,glessard/swift,tardieu/swift,atrick/swift,parkera/swift,rudkx/swift,swiftix/swift,shajrawi/swift,shajrawi/swift,practicalswift/swift,tinysun212/swift-windows,swiftix/swift,stephentyrone/swift,calebd/swift,djwbrown/swift,nathawes/swift,sschiau/swift,ben-ng/swift,uasys/swift,ahoppen/swift,roambotics/swift,xwu/swift,huonw/swift,deyton/swift,stephentyrone/swift,jmgc/swift,stephentyrone/swift,roambotics/swift,airspeedswift/swift,atrick/swift,rudkx/swift,danielmartin/swift,bitjammer/swift,zisko/swift,JGiola/swift,jmgc/swift,roambotics/swift,milseman/swift,hooman/swift,jtbandes/swift,calebd/swift,devincoughlin/swift,manavgabhawala/swift,zisko/swift,frootloops/swift,xedin/swift