This contains just enough for lib/Target/RISCV to compile. Notably a basic
RISCVTargetMachine and RISCVTargetInfo. At this point you can attempt llc
-march=riscv32 myinput.ll and will find it fails due to the lack of
MCAsmInfo.
See http://lists.llvm.org/pipermail/llvm-dev/2016-August/103748.html for
further discussion
Differential Revision: https://reviews.llvm.org/D23560
llvm-svn: 285712
Alex Bradbury