[clang] [alpha.webkit.UncountedCallArgsChecker] Treat CFEqual as a safe function (PR #146369)

[Ryosuke Niwa via cfe-commits]

================
@@ -45,6 +45,7 @@ CFDictionaryRef CFDictionaryCreateCopy(CFAllocatorRef allocator, CFDictionaryRef
 CFDictionaryRef CFDictionaryCreateMutableCopy(CFAllocatorRef allocator, CFIndex capacity, CFDictionaryRef theDict);
 CFIndex CFDictionaryGetCount(CFDictionaryRef theDict);
 Boolean CFDictionaryContainsKey(CFDictionaryRef theDict, const void *key);
+extern Boolean CFEqual(CFTypeRef, CFTypeRef);
----------------
rniwa wrote:

Do we need "extern" here?

https://github.com/llvm/llvm-project/pull/146369