[Support] Follow up to r204426, for LockFileManager, make the given path absolute so relative paths are properly handled in both Windows and Unix.

llvm-svn: 204520
diff --git a/llvm/lib/Support/LockFileManager.cpp b/llvm/lib/Support/LockFileManager.cpp
index 5585847..cd1cbcb 100644
--- a/llvm/lib/Support/LockFileManager.cpp
+++ b/llvm/lib/Support/LockFileManager.cpp
@@ -68,7 +68,11 @@
 LockFileManager::LockFileManager(StringRef FileName)
 {
   this->FileName = FileName;
-  LockFileName = FileName;
+  if (error_code EC = sys::fs::make_absolute(this->FileName)) {
+    Error = EC;
+    return;
+  }
+  LockFileName = this->FileName;
   LockFileName += ".lock";
 
   // If the lock file already exists, don't bother to try to create our own
@@ -116,8 +120,7 @@
   while (1) {
     // Create a link from the lock file name. If this succeeds, we're done.
     error_code EC =
-        sys::fs::create_link(sys::path::filename(UniqueLockFileName.str()),
-                             LockFileName.str());
+        sys::fs::create_link(UniqueLockFileName.str(), LockFileName.str());
     if (EC == errc::success)
       return;