tablegen problem with LLVM 2.5 cross build

I have been trying to cross compile LLVM for another platform but ran into a problem when feeding the standard config options into the configure script. It seems after fiddling with some of the variables I have one of two problems-

1) Makefile is not being generated for the BuildTools dir. (I am not sure what belongs here)

2) It thinks that the cross compiled tablegen is executible on the build platform.

Any advice would be appreciated.

Thanks in advance,