Make getDirnameSep a static method (not part of Path's interface).

llvm-svn: 49354
diff --git a/llvm/lib/System/Path.cpp b/llvm/lib/System/Path.cpp
index 43c36d5..e8fd5f2 100644
--- a/llvm/lib/System/Path.cpp
+++ b/llvm/lib/System/Path.cpp
@@ -196,7 +196,7 @@
         Paths.push_back(tmpPath);
 }
 
-std::string Path::getDirnameCharSep(char Sep) const {
+static std::string getDirnameCharSep(const std::string& path, char Sep) {
   
   if (path.empty())
     return ".";