cmake: add modified FindICU from CMake
cmake: add modified FindICU from CMake

e78l/swift-corelibs-foundation,apple/swift-corelibs-foundation,parkera/swift-corelibs-foundation,parkera/swift-corelibs-foundation,e78l/swift-corelibs-foundation,JGiola/swift-corelibs-foundation,JGiola/swift-corelibs-foundation,parkera/swift-corelibs-foundation,JGiola/swift-corelibs-foundation,e78l/swift-corelibs-foundation,parkera/swift-corelibs-foundation,JGiola/swift-corelibs-foundation,e78l/swift-corelibs-foundation,apple/swift-corelibs-foundation,parkera/swift-corelibs-foundation,JGiola/swift-corelibs-foundation,e78l/swift-corelibs-foundation,apple/swift-corelibs-foundation,apple/swift-corelibs-foundation,apple/swift-corelibs-foundation