libuv: Add fs_copy stub to cmake-bootstrap.c

This is now called by `uv__fs_sendfile` in `src/unix/fs.c` but we do not
need that feature during CMake bootstrap.

Utilities/cmlibuv/src/unix/cmake-bootstrap.c

@@ -152,4 +152,12 @@ int uv__statx(int dirfd,
   errno = ENOSYS;
   return -1;
 }
+
+ssize_t uv__fs_copy_file_range(int fd_in, ssize_t* off_in,
+                               int fd_out, ssize_t* off_out,
+                               size_t len, unsigned int flags)
+{
+  errno = ENOSYS;
+  return -1;
+}
 #endif