Hold reporter's IConfig instance in the interface

Previously, every base derived from the IStreamingReporter had
its own `IConfig const* m_config` member, so this just centralizes
the handling thereof.

Part of #2061

src/catch2/catch_session.cpp

@@ -48,7 +48,7 @@ namespace Catch {
             // doesn't compile without a std::move call. However, this causes
             // a warning on newer platforms. Thus, we have to work around
             // it a bit and downcast the pointer manually.
-            auto ret = Detail::unique_ptr<IStreamingReporter>(new ListeningReporter);
+            auto ret = Detail::unique_ptr<IStreamingReporter>(new ListeningReporter(config));
             auto& multi = static_cast<ListeningReporter&>(*ret);
             auto const& listeners = Catch::getRegistryHub().getReporterRegistry().getListeners();
             for (auto const& listener : listeners) {

src/catch2/interfaces/catch_interfaces_reporter.hpp

@@ -176,7 +176,12 @@ namespace Catch {
     protected:
         //! Derived classes can set up their preferences here
         ReporterPreferences m_preferences;
+        //! The test run's config as filled in from CLI and defaults
+        IConfig const* m_config;
+
     public:
+        IStreamingReporter( IConfig const* config ): m_config( config ) {}
+
         virtual ~IStreamingReporter() = default;
 
         // Implementing class must also provide the following static methods:

src/catch2/reporters/catch_reporter_cumulative_base.hpp

@@ -46,7 +46,8 @@ namespace Catch {
         using TestRunNode = Node<TestRunStats, TestGroupNode>;
 
         CumulativeReporterBase( ReporterConfig const& _config ):
-            m_config( _config.fullConfig() ), stream( _config.stream() ) {}
+            IStreamingReporter( _config.fullConfig() ),
+            stream( _config.stream() ) {}
         ~CumulativeReporterBase() override;
 
         void testRunStarting( TestRunInfo const& ) override {}
@@ -68,7 +69,6 @@ namespace Catch {
 
         void skipTest(TestCaseInfo const&) override {}
 
-        IConfig const* m_config;
         std::ostream& stream;
         // Note: We rely on pointer identity being stable, which is why
         //       which is why we store around pointers rather than values.

src/catch2/reporters/catch_reporter_event_listener.hpp

@@ -20,11 +20,9 @@ namespace Catch {
      * member functions it actually cares about.
      */
     class EventListenerBase : public IStreamingReporter {
-        IConfig const* m_config;
-
     public:
         EventListenerBase( ReporterConfig const& config ):
-            m_config( config.fullConfig() ) {}
+            IStreamingReporter( config.fullConfig() ) {}
 
         void assertionStarting( AssertionInfo const& assertionInfo ) override;
         bool assertionEnded( AssertionStats const& assertionStats ) override;

src/catch2/reporters/catch_reporter_listening.cpp

@@ -11,11 +11,6 @@
 
 namespace Catch {
 
-    ListeningReporter::ListeningReporter() {
-        // We will assume that listeners will always want all assertions
-        m_preferences.shouldReportAllAssertions = true;
-    }
-
     void ListeningReporter::addListener( IStreamingReporterPtr&& listener ) {
         m_listeners.push_back( std::move( listener ) );
     }

src/catch2/reporters/catch_reporter_listening.hpp

@@ -18,7 +18,12 @@ namespace Catch {
         IStreamingReporterPtr m_reporter = nullptr;
 
     public:
-        ListeningReporter();
+        ListeningReporter( IConfig const* config ):
+            IStreamingReporter( config ) {
+            // We will assume that listeners will always want all assertions
+            m_preferences.shouldReportAllAssertions = true;
+        }
+
 
         void addListener( IStreamingReporterPtr&& listener );
         void addReporter( IStreamingReporterPtr&& reporter );

src/catch2/reporters/catch_reporter_streaming_base.hpp

@@ -36,8 +36,8 @@ namespace Catch {
     struct StreamingReporterBase : IStreamingReporter {
 
         StreamingReporterBase( ReporterConfig const& _config ):
-            m_config( _config.fullConfig() ), stream( _config.stream() ) {
-        }
+            IStreamingReporter( _config.fullConfig() ),
+            stream( _config.stream() ) {}
 
 
         ~StreamingReporterBase() override;
@@ -71,7 +71,6 @@ namespace Catch {
             // It can optionally be overridden in the derived class.
         }
 
-        IConfig const* m_config;
         std::ostream& stream;
 
         LazyStat<TestRunInfo> currentTestRunInfo;