Swift: Fix some C++20 todos.

Author: sashabu

swift/extractor/trap/TrapLabel.h

@@ -1,11 +1,11 @@
 #pragma once
 
+#include <bit>
 #include <cassert>
 #include <iomanip>
 #include <iostream>
 #include <string>
 #include <vector>
-#include "absl/numeric/bits.h"
 #include <binlog/binlog.hpp>
 #include <cmath>
 #include <charconv>
@@ -52,7 +52,7 @@ class UntypedTrapLabel {
   size_t strSize() const {
     if (id_ == 0) return 2;  // #0
     // Number of hex digits is ceil(bit_width(id) / 4), but C++ integer division can only do floor.
-    return /* # */ 1 + /* hex digits */ 1 + (absl::bit_width(id_) - 1) / 4;
+    return /* # */ 1 + /* hex digits */ 1 + (std::bit_width(id_) - 1) / 4;
   }
 
   friend bool operator!=(UntypedTrapLabel lhs, UntypedTrapLabel rhs) { return lhs.id_ != rhs.id_; }

swift/logging/SwiftLogging.h

@@ -55,15 +55,14 @@
 #define DIAGNOSE_CRITICAL(ID, ...) DIAGNOSE_WITH_LEVEL(critical, ID, __VA_ARGS__)
 
 #define CODEQL_DIAGNOSTIC_LOG_FORMAT_PREFIX "[{}] "
-// TODO(C++20) replace non-standard , ##__VA_ARGS__ with __VA_OPT__(,) __VA_ARGS__
 #define DIAGNOSE_WITH_LEVEL(LEVEL, ID, FORMAT, ...)                                  \
   do {                                                                               \
     auto _now = ::binlog::clockNow();                                                \
     const ::codeql::SwiftDiagnostic& _id = ID;                                       \
     ::codeql::Log::diagnose(_id, std::chrono::nanoseconds{_now},                     \
-                            fmt::format(FORMAT, ##__VA_ARGS__));                     \
+                            fmt::format(FORMAT __VA_OPT__(, ) __VA_ARGS__));         \
     LOG_WITH_LEVEL_AND_TIME(LEVEL, _now, CODEQL_DIAGNOSTIC_LOG_FORMAT_PREFIX FORMAT, \
-                            _id.abbreviation(), ##__VA_ARGS__);                      \
+                            _id.abbreviation() __VA_OPT__(, ) __VA_ARGS__);          \
   } while (false)
 
 // avoid calling into binlog's original macros