Add a wrapper for open.

This centralizes the handling of O_BINARY and opens the way for hiding more
differences (like how open behaves with directories).

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@186447 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/tools/llvm-mc/llvm-mc.cpp b/tools/llvm-mc/llvm-mc.cpp
index 26c99d5..f10a614 100644
--- a/tools/llvm-mc/llvm-mc.cpp
+++ b/tools/llvm-mc/llvm-mc.cpp
@@ -210,8 +210,8 @@
     OutputFilename = "-";
 
   std::string Err;
-  tool_output_file *Out = new tool_output_file(OutputFilename.c_str(), Err,
-                                               raw_fd_ostream::F_Binary);
+  tool_output_file *Out =
+      new tool_output_file(OutputFilename.c_str(), Err, sys::fs::F_Binary);
   if (!Err.empty()) {
     errs() << Err << '\n';
     delete Out;