Add support for getting file system permissions and implement sys::fs::permissions to set them.

Patch by James Henderson.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@297617 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Support/Path.cpp

@@ -1189,12 +1189,20 @@ std::error_code identify_magic(const Twine &Path, file_magic &Result) {
 }
 
 std::error_code directory_entry::status(file_status &result) const {
-  return fs::status(Path, result, FollowSymlinks);
-}
-
-} // end namespace fs
-} // end namespace sys
-} // end namespace llvm
+  return fs::status(Path, result, FollowSymlinks);
+}
+
+ErrorOr<perms> getPermissions(const Twine &Path) {
+  file_status Status;
+  if (std::error_code EC = status(Path, Status))
+    return EC;
+
+  return Status.permissions();
+}
+
+} // end namespace fs
+} // end namespace sys
+} // end namespace llvm
 
 // Include the truly platform-specific parts.
 #if defined(LLVM_ON_UNIX)