[clang-tools-extra] Add ability to pass in a clang-tidy config file to clang-tidy-diff (PR #75721)

[Chris Apple via cfe-commits]

https://github.com/cjappl created https://github.com/llvm/llvm-project/pull/75721

I found this handy for situations where you want to pass in a config file and not rely on a default `.clang-tidy` file.


The new option is `-config` and will expect something that can be passed into the `--config-file=` parameter of `clang-tidy`

>From 433f4ac919a6967c278e56a19b5824e474ebd907 Mon Sep 17 00:00:00 2001
From: Chris Apple <14171107+cjappl at users.noreply.github.com>
Date: Sat, 16 Dec 2023 15:53:56 -0800
Subject: [PATCH] Add ability to pass in a clang-tidy config file to
 clang-tidy-diff

---
 clang-tools-extra/clang-tidy/tool/clang-tidy-diff.py | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/clang-tools-extra/clang-tidy/tool/clang-tidy-diff.py b/clang-tools-extra/clang-tidy/tool/clang-tidy-diff.py
index 8817e2914f6e25..fdaf1a4330e060 100755
--- a/clang-tools-extra/clang-tidy/tool/clang-tidy-diff.py
+++ b/clang-tools-extra/clang-tidy/tool/clang-tidy-diff.py
@@ -223,6 +223,12 @@ def main():
         default=[],
         help="Load the specified plugin in clang-tidy.",
     )
+    parser.add_argument(
+        "-config",
+        dest="config",
+        default=None,
+        help="Specifies a clang-tidy config file"
+    )
 
     clang_tidy_args = []
     argv = sys.argv[1:]
@@ -309,6 +315,8 @@ def main():
 
     # Form the common args list.
     common_clang_tidy_args = []
+    if args.config is not None:
+        common_clang_tidy_args.append("--config-file=" + args.config)
     if args.fix:
         common_clang_tidy_args.append("-fix")
     if args.checks != "":