libuv: Add a check which copies files when creating a link fails

Due to the fact that I use exFAT on my development drive so that I can connect it to my Android phone, I found it quite annoying that CMake completely fails when I try to compile dependencies that use any sort of links or shared libraries while I'm running Linux. I decided to try to fix this issue, and managed to do so by adding a simple check after either kind of link has failed to be created and retries the same thing but copying the file instead.