[clang-tools-extra] [clang-tidy] add depercation warning for non-whitelisted global options (PR #121057)

[Carlos Galvez via cfe-commits]

================
@@ -62,16 +62,29 @@ ClangTidyCheck::OptionsView::get(StringRef LocalName) const {
   return std::nullopt;
 }
 
+static const llvm::StringSet<> DeprecatedGlobalOptions{
+    "StrictMode",
+    "IgnoreMacros",
+};
+
 static ClangTidyOptions::OptionMap::const_iterator
 findPriorityOption(const ClangTidyOptions::OptionMap &Options,
                    StringRef NamePrefix, StringRef LocalName,
-                   llvm::StringSet<> *Collector) {
+                   ClangTidyContext *Context) {
+  llvm::StringSet<> *Collector = Context->getOptionsCollector();
   if (Collector) {
     Collector->insert((NamePrefix + LocalName).str());
     Collector->insert(LocalName);
   }
   auto IterLocal = Options.find((NamePrefix + LocalName).str());
   auto IterGlobal = Options.find(LocalName);
+  // FIXME: temporary solution for deprecation warnings, should be removed
+  // after 22.x.
+  if (IterGlobal != Options.end() &&
+      DeprecatedGlobalOptions.contains(LocalName))
+    Context->configurationDiag(
+        "deprecation global option '%0', please use '%1%0'.")
----------------
carlosgalvezp wrote:

I believe this would be clearer:

```
"global option '%0' is deprecated, please use '%1%0' instead."
```

https://github.com/llvm/llvm-project/pull/121057