[bootstrap] Prefix -F with -Xcc for corelibs
[bootstrap] Prefix -F with -Xcc for corelibs

sschiau/swift-package-manager,JGiola/swift-package-manager,abertelrud/swift-package-manager,abertelrud/swift-package-manager,apple/swift-package-manager,abertelrud/swift-package-manager,JGiola/swift-package-manager,sschiau/swift-package-manager,apple/swift-package-manager,JGiola/swift-package-manager,sschiau/swift-package-manager,apple/swift-package-manager,apple/swift-package-manager,JGiola/swift-package-manager,abertelrud/swift-package-manager,apple/swift-package-manager,abertelrud/swift-package-manager,sschiau/swift-package-manager,sschiau/swift-package-manager,JGiola/swift-package-manager