Split apart combined TUs

The compile time improvements from using combined TUs mostly isn't
worth the annoyance they cause with various IDE shortcuts, like
when switching between header and its impl. file.

Splitting them apart also fixes the issue of empty subdirs being
installed due to `foo/internal` folders that only contained the
combined TUs and no headers.

Closes #2457
Closes #2463

src/catch2/interfaces/catch_interfaces_capture.cpp

@@ -0,0 +1,13 @@
+
+//              Copyright Catch2 Authors
+// Distributed under the Boost Software License, Version 1.0.
+//   (See accompanying file LICENSE_1_0.txt or copy at
+//        https://www.boost.org/LICENSE_1_0.txt)
+
+// SPDX-License-Identifier: BSL-1.0
+
+#include <catch2/interfaces/catch_interfaces_capture.hpp>
+
+namespace Catch {
+    IResultCapture::~IResultCapture() = default;
+}

src/catch2/interfaces/catch_interfaces_combined_tu.cpp

@@ -1,90 +0,0 @@
-
-//              Copyright Catch2 Authors
-// Distributed under the Boost Software License, Version 1.0.
-//   (See accompanying file LICENSE_1_0.txt or copy at
-//        https://www.boost.org/LICENSE_1_0.txt)
-
-// SPDX-License-Identifier: BSL-1.0
-/** \file
- * This is a special TU that combines what would otherwise be a very
- * small interfaces-related TUs into one bigger TU.
- *
- * The reason for this is compilation performance improvements by
- * avoiding reparsing headers for many small TUs, instead having this
- * one TU include bit more, but having it all parsed only once.
- *
- * To avoid heavy-tail problem with compilation times, each "subpart"
- * of Catch2 has its own combined TU like this.
- */
-
-///////////////////////////////////////////////////
-// vvv formerly catch_interfaces_capture.cpp vvv //
-///////////////////////////////////////////////////
-
-#include <catch2/interfaces/catch_interfaces_capture.hpp>
-
-namespace Catch {
-    IResultCapture::~IResultCapture() = default;
-}
-
-
-//////////////////////////////////////////////////
-// vvv formerly catch_interfaces_config.cpp vvv //
-//////////////////////////////////////////////////
-
-#include <catch2/interfaces/catch_interfaces_config.hpp>
-
-namespace Catch {
-    IConfig::~IConfig() = default;
-}
-
-
-/////////////////////////////////////////////////////
-// vvv formerly catch_interfaces_exception.cpp vvv //
-/////////////////////////////////////////////////////
-
-#include <catch2/interfaces/catch_interfaces_exception.hpp>
-
-namespace Catch {
-    IExceptionTranslator::~IExceptionTranslator() = default;
-    IExceptionTranslatorRegistry::~IExceptionTranslatorRegistry() = default;
-}
-
-
-////////////////////////////////////////////////////////
-// vvv formerly catch_interfaces_registry_hub.cpp vvv //
-////////////////////////////////////////////////////////
-
-#include <catch2/interfaces/catch_interfaces_registry_hub.hpp>
-
-namespace Catch {
-    IRegistryHub::~IRegistryHub() = default;
-    IMutableRegistryHub::~IMutableRegistryHub() = default;
-}
-
-
-////////////////////////////////////////////////////
-// vvv formerly catch_interfaces_testcase.cpp vvv //
-////////////////////////////////////////////////////
-
-#include <catch2/interfaces/catch_interfaces_testcase.hpp>
-
-namespace Catch {
-    ITestInvoker::~ITestInvoker() = default;
-    ITestCaseRegistry::~ITestCaseRegistry() = default;
-}
-
-
-#include <catch2/interfaces/catch_interfaces_reporter_registry.hpp>
-
-namespace Catch {
-    IReporterRegistry::~IReporterRegistry() = default;
-}
-
-
-#include <catch2/interfaces/catch_interfaces_reporter_factory.hpp>
-
-namespace Catch {
-    IReporterFactory::~IReporterFactory() = default;
-    EventListenerFactory::~EventListenerFactory() = default;
-}

src/catch2/interfaces/catch_interfaces_config.cpp

@@ -0,0 +1,13 @@
+
+//              Copyright Catch2 Authors
+// Distributed under the Boost Software License, Version 1.0.
+//   (See accompanying file LICENSE_1_0.txt or copy at
+//        https://www.boost.org/LICENSE_1_0.txt)
+
+// SPDX-License-Identifier: BSL-1.0
+
+#include <catch2/interfaces/catch_interfaces_config.hpp>
+
+namespace Catch {
+    IConfig::~IConfig() = default;
+}

src/catch2/interfaces/catch_interfaces_exception.cpp

@@ -0,0 +1,14 @@
+
+//              Copyright Catch2 Authors
+// Distributed under the Boost Software License, Version 1.0.
+//   (See accompanying file LICENSE_1_0.txt or copy at
+//        https://www.boost.org/LICENSE_1_0.txt)
+
+// SPDX-License-Identifier: BSL-1.0
+
+#include <catch2/interfaces/catch_interfaces_exception.hpp>
+
+namespace Catch {
+    IExceptionTranslator::~IExceptionTranslator() = default;
+    IExceptionTranslatorRegistry::~IExceptionTranslatorRegistry() = default;
+}

src/catch2/interfaces/catch_interfaces_registry_hub.cpp

@@ -0,0 +1,14 @@
+
+//              Copyright Catch2 Authors
+// Distributed under the Boost Software License, Version 1.0.
+//   (See accompanying file LICENSE_1_0.txt or copy at
+//        https://www.boost.org/LICENSE_1_0.txt)
+
+// SPDX-License-Identifier: BSL-1.0
+
+#include <catch2/interfaces/catch_interfaces_registry_hub.hpp>
+
+namespace Catch {
+    IRegistryHub::~IRegistryHub() = default;
+    IMutableRegistryHub::~IMutableRegistryHub() = default;
+}

src/catch2/interfaces/catch_interfaces_reporter_factory.cpp

@@ -0,0 +1,14 @@
+
+//              Copyright Catch2 Authors
+// Distributed under the Boost Software License, Version 1.0.
+//   (See accompanying file LICENSE_1_0.txt or copy at
+//        https://www.boost.org/LICENSE_1_0.txt)
+
+// SPDX-License-Identifier: BSL-1.0
+
+#include <catch2/interfaces/catch_interfaces_reporter_factory.hpp>
+
+namespace Catch {
+    IReporterFactory::~IReporterFactory() = default;
+    EventListenerFactory::~EventListenerFactory() = default;
+}

src/catch2/interfaces/catch_interfaces_reporter_registry.cpp

@@ -0,0 +1,13 @@
+
+//              Copyright Catch2 Authors
+// Distributed under the Boost Software License, Version 1.0.
+//   (See accompanying file LICENSE_1_0.txt or copy at
+//        https://www.boost.org/LICENSE_1_0.txt)
+
+// SPDX-License-Identifier: BSL-1.0
+
+#include <catch2/interfaces/catch_interfaces_reporter_registry.hpp>
+
+namespace Catch {
+    IReporterRegistry::~IReporterRegistry() = default;
+}

src/catch2/interfaces/catch_interfaces_testcase.cpp

@@ -0,0 +1,14 @@
+
+//              Copyright Catch2 Authors
+// Distributed under the Boost Software License, Version 1.0.
+//   (See accompanying file LICENSE_1_0.txt or copy at
+//        https://www.boost.org/LICENSE_1_0.txt)
+
+// SPDX-License-Identifier: BSL-1.0
+
+#include <catch2/interfaces/catch_interfaces_testcase.hpp>
+
+namespace Catch {
+    ITestInvoker::~ITestInvoker() = default;
+    ITestCaseRegistry::~ITestCaseRegistry() = default;
+}