[haskell-llvm] TARGET detection

[Henning Thielemann]

There are two methods in llvm-base for detecting the host target and 
adapting LLVM.Target.Native to it:

1) The configure script scans the output of $(llvm-config --libs) and 
extracts the target portion of libLLVM*CodeGen. Then it replaces the 
keyword TARGET in LLVM.Target.Native with the detected target.

2) The module LLVM.Target.Native calls the macro 
LLVMInitializeNativeTarget from llvm-c/Target.h which does the right 
thing.


The second method is the one that is currently used. I propose to remove 
the first one since it is complicated and seems to be fragile.