Extracted ObjCARC.cpp into its own library libLLVMObjCARCOpts in preparation for refactoring the ARC Optimizer.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@173647 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/LLVMBuild.txt b/lib/CodeGen/LLVMBuild.txt
index fee0347..81ef1aa 100644
--- a/lib/CodeGen/LLVMBuild.txt
+++ b/lib/CodeGen/LLVMBuild.txt
@@ -22,4 +22,4 @@
 type = Library
 name = CodeGen
 parent = Libraries
-required_libraries = Analysis Core MC Scalar Support Target TransformUtils
+required_libraries = Analysis Core MC Scalar Support Target TransformUtils ObjCARC