Adding Makefile so we can configure upc2c tool.

Makefile

@@ -0,0 +1,24 @@
+##===- clang-upc2c/Makefile --------------------------------*- Makefile -*-===##
+#
+#                     The LLVM Compiler Infrastructure
+#
+# This file is distributed under the University of Illinois Open Source
+# License. See LICENSE.TXT for details.
+#
+##===----------------------------------------------------------------------===##
+
+CLANG_LEVEL := ../..
+
+TOOLNAME = clang-upc2c
+
+# No plugins, optimize startup time.
+TOOL_NO_EXPORTS = 1
+
+include $(CLANG_LEVEL)/../../Makefile.config
+LINK_COMPONENTS := $(TARGETS_TO_BUILD) asmparser bitreader support mc option
+USEDLIBS = clangFormat.a clangTooling.a clangFrontend.a clangSerialization.a \
+	   clangDriver.a clangParse.a clangSema.a clangAnalysis.a \
+           clangRewriteFrontend.a clangRewriteCore.a clangEdit.a clangAST.a \
+           clangLex.a clangBasic.a 
+
+include $(CLANG_LEVEL)/Makefile