Only calcuate $*TZ the first time we need it.
Only calcuate $*TZ the first time we need it.

This calculation used to be 7.19% of the time spent loading setting
on my box; on others where rel2abs isn't so terribly expensive it
probably counted for more.

salortiz/rakudo,Leont/rakudo,nunorc/rakudo,azawawi/rakudo,tony-o/deb-rakudodaily,lucasbuchala/rakudo,cognominal/rakudo,samcv/rakudo,teodozjan/rakudo,nbrown/rakudo,samcv/rakudo,zhuomingliang/rakudo,usev6/rakudo,retupmoca/rakudo,rakudo/rakudo,softmoth/rakudo,tony-o/deb-rakudodaily,zostay/rakudo,retupmoca/rakudo,awwaiid/rakudo,salortiz/rakudo,teodozjan/rakudo,tbrowder/rakudo,dankogai/rakudo,softmoth/rakudo,jonathanstowe/rakudo,cognominal/rakudo,dankogai/rakudo,niner/rakudo,labster/rakudo,MasterDuke17/rakudo,b2gills/rakudo,sergot/rakudo,rakudo/rakudo,zostay/rakudo,paultcochrane/rakudo,sjn/rakudo,tony-o/deb-rakudodaily,awwaiid/rakudo,MasterDuke17/rakudo,jonathanstowe/rakudo,dankogai/rakudo,laben/rakudo,niner/rakudo,sergot/rakudo,samcv/rakudo,nbrown/rakudo,LLFourn/rakudo,MasterDuke17/rakudo,nunorc/rakudo,retupmoca/rakudo,ab5tract/rakudo,tony-o/rakudo,dankogai/rakudo,lucasbuchala/rakudo,zhuomingliang/rakudo,cygx/rakudo,jonathanstowe/rakudo,azawawi/rakudo,LLFourn/rakudo,ugexe/rakudo,labster/rakudo,skids/rakudo,cygx/rakudo,tony-o/rakudo,ab5tract/rakudo,sjn/rakudo,samcv/rakudo,usev6/rakudo,paultcochrane/rakudo,tbrowder/rakudo,awwaiid/rakudo,retupmoca/rakudo,nbrown/rakudo,lucasbuchala/rakudo,labster/rakudo,ab5tract/rakudo,teodozjan/rakudo,raydiak/rakudo,ungrim97/rakudo,tony-o/deb-rakudodaily,salortiz/rakudo,usev6/rakudo,rakudo/rakudo,cognominal/rakudo,awwaiid/rakudo,tbrowder/rakudo,sjn/rakudo,usev6/rakudo,Gnouc/rakudo,softmoth/rakudo,Leont/rakudo,nbrown/rakudo,ungrim97/rakudo,cognominal/rakudo,nunorc/rakudo,jonathanstowe/rakudo,softmoth/rakudo,ugexe/rakudo,zhuomingliang/rakudo,azawawi/rakudo,paultcochrane/rakudo,b2gills/rakudo,tony-o/deb-rakudodaily,raydiak/rakudo,sergot/rakudo,zostay/rakudo,samcv/rakudo,tony-o/deb-rakudodaily,softmoth/rakudo,ungrim97/rakudo,ungrim97/rakudo,Gnouc/rakudo,nbrown/rakudo,Leont/rakudo,jonathanstowe/rakudo,Leont/rakudo,MasterDuke17/rakudo,Gnouc/rakudo,ugexe/rakudo,MasterDuke17/rakudo,ab5tract/rakudo,LLFourn/rakudo,sjn/rakudo,awwaiid/rakudo,raydiak/rakudo,rakudo/rakudo,skids/rakudo,MasterDuke17/rakudo,teodozjan/rakudo,raydiak/rakudo,lucasbuchala/rakudo,cygx/rakudo,ugexe/rakudo,nunorc/rakudo,dankogai/rakudo,nbrown/rakudo,labster/rakudo,Gnouc/rakudo,sjn/rakudo,laben/rakudo,b2gills/rakudo,labster/rakudo,ugexe/rakudo,b2gills/rakudo,tony-o/rakudo,tbrowder/rakudo,rakudo/rakudo,niner/rakudo,paultcochrane/rakudo,cognominal/rakudo,zostay/rakudo,ab5tract/rakudo,b2gills/rakudo,cygx/rakudo,usev6/rakudo,labster/rakudo,salortiz/rakudo,salortiz/rakudo,sergot/rakudo,paultcochrane/rakudo,salortiz/rakudo,skids/rakudo,azawawi/rakudo,tony-o/rakudo,ungrim97/rakudo,zhuomingliang/rakudo,tony-o/deb-rakudodaily,tony-o/rakudo,LLFourn/rakudo,Gnouc/rakudo,Gnouc/rakudo,lucasbuchala/rakudo,niner/rakudo,laben/rakudo,tbrowder/rakudo,rakudo/rakudo,skids/rakudo,tbrowder/rakudo,azawawi/rakudo,cygx/rakudo,LLFourn/rakudo,laben/rakudo,tony-o/rakudo,skids/rakudo