Pass StringRef by value.

llvm-svn: 86251
diff --git a/llvm/lib/Linker/LinkItems.cpp b/llvm/lib/Linker/LinkItems.cpp
index 61f3c26..494a013 100644
--- a/llvm/lib/Linker/LinkItems.cpp
+++ b/llvm/lib/Linker/LinkItems.cpp
@@ -70,7 +70,7 @@
 
 /// LinkInLibrary - links one library into the HeadModule.
 ///
-bool Linker::LinkInLibrary(const StringRef &Lib, bool& is_native) {
+bool Linker::LinkInLibrary(StringRef Lib, bool& is_native) {
   is_native = false;
   // Determine where this library lives.
   sys::Path Pathname = FindLib(Lib);