Makefile: Corresponding to r172787, "Backend.cpp: s/TARGET_NAME/TARGET_TRIPLE/ Also TARGET_TRIPLE can be normalized as well as TARGET_NAME."

I forgot to commit it by mistake, sorry.

git-svn-id: https://llvm.org/svn/llvm-project/dragonegg/trunk@172790 91177308-0d34-0410-b5e6-96231b3b80d8