Fix name matching to work on windows.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@189517 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/tools/llvm-ar/llvm-ar.cpp b/tools/llvm-ar/llvm-ar.cpp
index f47b0a6..e56e49ad 100644
--- a/tools/llvm-ar/llvm-ar.cpp
+++ b/tools/llvm-ar/llvm-ar.cpp
@@ -876,9 +876,10 @@
     "  This program archives bitcode files into single libraries\n"
   );
 
-  if (ToolName.endswith("ar"))
+  StringRef Stem = sys::path::stem(ToolName);
+  if (Stem.endswith("ar"))
     return ar_main(argv);
-  if (ToolName.endswith("ranlib"))
+  if (Stem.endswith("ranlib"))
     return ranlib_main();
   fail("Not ranlib or ar!");
 }