rust-llvm: convert to cmake build

Future versions of LLVM require cmake to build so it will be easier to
prove that out on a known good build and to allow future versions to use
this as common code.

recipes-devtools/rust/files/rust-llvm/0001-Don-t-build-unittests.patch

@@ -1,34 +0,0 @@
-From eee79cc95f57434c4b530da96c88494e9b5d056b Mon Sep 17 00:00:00 2001
-From: Steven Walter <stevenrwalter@gmail.com>
-Date: Sat, 27 Aug 2016 13:20:48 -0400
-Subject: [PATCH] Don't build unittests
-
----
- Makefile | 4 ++--
- 1 file changed, 2 insertions(+), 2 deletions(-)
-
-diff --git a/Makefile b/Makefile
-index 2b9468a..2bb30f6 100644
---- a/Makefile
-+++ b/Makefile
-@@ -31,7 +31,7 @@ ifeq ($(BUILD_DIRS_ONLY),1)
-   OPTIONAL_DIRS := tools/clang/utils/TableGen
- else
-   DIRS := lib/Support lib/TableGen utils lib/IR lib tools/llvm-shlib \
--          tools/llvm-config tools docs cmake unittests
-+          tools/llvm-config tools docs cmake
-   OPTIONAL_DIRS := projects bindings
- endif
- 
-@@ -39,7 +39,7 @@ ifeq ($(BUILD_EXAMPLES),1)
-   OPTIONAL_DIRS += examples
- endif
- 
--EXTRA_DIST := test unittests llvm.spec include win32 Xcode
-+EXTRA_DIST := test llvm.spec include win32 Xcode
- 
- include $(LEVEL)/Makefile.config
- 
--- 
-2.7.4
-