Always make sure that you follow the instructions exactly. A lot of the problems that get reported are caused by some apparently minor deviation from these instructions, but they still take time to track down. Take special care with the target triplets specified during the configure step.

One common problem is lack of disk space. Building a full toolchain requires a lot of disk space, especially on a FAT-based file system. If you come across a strange toolchain build failure then please check there is plenty of disk space available on all the relevant drives.