[llvm] [llvm-ml] Adds /quiet flag to llvm-ml (PR #107308)

[Matt Bolitho via llvm-commits]

https://github.com/MattBolitho created https://github.com/llvm/llvm-project/pull/107308

In PR #106794, it was noted that `llvm-ml` does not support the `/quiet` flag. The original reason it was added by Microsoft to `ml`/`ml64` was to remove extraneous CMake build output (see [CMake GitLab issue](https://gitlab.kitware.com/cmake/cmake/-/issues/23537)) much like in the linked PR .

If the goal is for `llvm-ml` to be a drop-in replacement for `ml`/`ml64`, then I think it makes sense to support the `/quiet` flag, much like how `/nologo` is supported.

>From c1f4a200a64ab0ba64b4c7f32c41f524abd1034a Mon Sep 17 00:00:00 2001
From: Matt Bolitho <matt.bolitho.software at gmail.com>
Date: Mon, 2 Sep 2024 23:44:26 +0100
Subject: [PATCH] Adds /quiet flag to llvm-ml

---
 llvm/tools/llvm-ml/Opts.td | 1 +
 1 file changed, 1 insertion(+)

diff --git a/llvm/tools/llvm-ml/Opts.td b/llvm/tools/llvm-ml/Opts.td
index 686edded23b853..8b748bb64b278b 100644
--- a/llvm/tools/llvm-ml/Opts.td
+++ b/llvm/tools/llvm-ml/Opts.td
@@ -72,6 +72,7 @@ def define : MLJoinedOrSeparate<"D">, MetaVarName<"<macro>=<value>">,
              HelpText<"Define <macro> to <value> (or blank if <value> "
                       "omitted)">;
 def no_logo : MLFlag<"nologo">, HelpText<"">;
+def quiet : MLFlag<"quiet">, HelpText<"">;
 def output_file : MLJoinedOrSeparate<"Fo">, HelpText<"Names the output file">;
 def include_path : MLJoinedOrSeparate<"I">,
                    HelpText<"Sets path for include files">;