Do not include chrono_clock.hpp in benchmark_stats_fwd.hpp

src/catch2/benchmark/detail/catch_benchmark_stats.hpp

@@ -8,6 +8,7 @@
 #ifndef CATCH_BENCHMARK_STATS_HPP_INCLUDED
 #define CATCH_BENCHMARK_STATS_HPP_INCLUDED
 
+#include <catch2/benchmark/catch_clock.hpp>
 #include <catch2/benchmark/catch_estimate.hpp>
 #include <catch2/benchmark/catch_outlier_classification.hpp>
 // The fwd decl & default specialization needs to be seen by VS2017 before

src/catch2/benchmark/detail/catch_benchmark_stats_fwd.hpp

@@ -8,14 +8,16 @@
 #ifndef CATCH_BENCHMARK_STATS_FWD_HPP_INCLUDED
 #define CATCH_BENCHMARK_STATS_FWD_HPP_INCLUDED
 
-#include <catch2/benchmark/catch_clock.hpp>
-
 namespace Catch {
 
+    namespace Detail {
+        struct DummyTemplateArgPlaceholder;
+    }
+
     // We cannot forward declare the type with default template argument
     // multiple times, so it is split out into a separate header so that
     // we can prevent multiple declarations in dependencies
-    template <typename Duration = Benchmark::FDuration>
+    template <typename Duration = Detail::DummyTemplateArgPlaceholder>
     struct BenchmarkStats;
 
 } // end namespace Catch