Split CATCH_CONFIG_WCHAR into its own header

Part of #2041

src/CMakeLists.txt

@@ -53,6 +53,7 @@ set(INTERNAL_HEADERS
     ${SOURCES_DIR}/catch_config.hpp
     ${SOURCES_DIR}/internal/catch_config_android_logwrite.hpp
     ${SOURCES_DIR}/internal/catch_config_uncaught_exceptions.hpp
+    ${SOURCES_DIR}/internal/catch_config_wchar.hpp
     ${SOURCES_DIR}/internal/catch_console_colour.hpp
     ${SOURCES_DIR}/internal/catch_context.hpp
     ${SOURCES_DIR}/internal/catch_debug_console.hpp

src/catch2/catch_all.hpp

@@ -52,6 +52,7 @@
 #include <catch2/internal/catch_compiler_capabilities.hpp>
 #include <catch2/internal/catch_config_android_logwrite.hpp>
 #include <catch2/internal/catch_config_uncaught_exceptions.hpp>
+#include <catch2/internal/catch_config_wchar.hpp>
 #include <catch2/internal/catch_console_colour.hpp>
 #include <catch2/internal/catch_console_width.hpp>
 #include <catch2/internal/catch_container_nonmembers.hpp>

src/catch2/catch_session.hpp

@@ -12,7 +12,7 @@
 #include <catch2/internal/catch_noncopyable.hpp>
 #include <catch2/catch_config.hpp>
 #include <catch2/internal/catch_unique_ptr.hpp>
-#include <catch2/internal/catch_compiler_capabilities.hpp>
+#include <catch2/internal/catch_config_wchar.hpp>
 
 namespace Catch {
 

src/catch2/catch_tostring.hpp

@@ -14,6 +14,7 @@
 #include <type_traits>
 #include <string>
 #include <catch2/internal/catch_compiler_capabilities.hpp>
+#include <catch2/internal/catch_config_wchar.hpp>
 #include <catch2/internal/catch_stream.hpp>
 #include <catch2/interfaces/catch_interfaces_enum_values_registry.hpp>
 
@@ -162,7 +163,7 @@ namespace Catch {
         static std::string convert(char * str);
     };
 
-#ifdef CATCH_CONFIG_WCHAR
+#if defined(CATCH_CONFIG_WCHAR)
     template<>
     struct StringMaker<std::wstring> {
         static std::string convert(const std::wstring& wstr);
@@ -183,7 +184,7 @@ namespace Catch {
     struct StringMaker<wchar_t *> {
         static std::string convert(wchar_t * str);
     };
-#endif
+#endif // CATCH_CONFIG_WCHAR
 
     // TBD: Should we use `strnlen` to ensure that we don't go out of the buffer,
     //      while keeping string semantics?

src/catch2/internal/catch_compiler_capabilities.hpp

@@ -186,11 +186,6 @@
 #  define CATCH_INTERNAL_CONFIG_EXCEPTIONS_ENABLED
 #endif
 
-////////////////////////////////////////////////////////////////////////////////
-// DJGPP
-#ifdef __DJGPP__
-#  define CATCH_INTERNAL_CONFIG_NO_WCHAR
-#endif // __DJGPP__
 
 ////////////////////////////////////////////////////////////////////////////////
 // Embarcadero C++Build
@@ -273,10 +268,6 @@
 #if defined(CATCH_INTERNAL_CONFIG_POSIX_SIGNALS) && !defined(CATCH_INTERNAL_CONFIG_NO_POSIX_SIGNALS) && !defined(CATCH_CONFIG_NO_POSIX_SIGNALS) && !defined(CATCH_CONFIG_POSIX_SIGNALS)
 #   define CATCH_CONFIG_POSIX_SIGNALS
 #endif
-// This is set by default, because we assume that compilers with no wchar_t support are just rare exceptions.
-#if !defined(CATCH_INTERNAL_CONFIG_NO_WCHAR) && !defined(CATCH_CONFIG_NO_WCHAR) && !defined(CATCH_CONFIG_WCHAR)
-#   define CATCH_CONFIG_WCHAR
-#endif
 
 #if !defined(CATCH_INTERNAL_CONFIG_NO_CPP11_TO_STRING) && !defined(CATCH_CONFIG_NO_CPP11_TO_STRING) && !defined(CATCH_CONFIG_CPP11_TO_STRING)
 #    define CATCH_CONFIG_CPP11_TO_STRING

src/catch2/internal/catch_config_wchar.hpp

@@ -0,0 +1,33 @@
+
+//              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
+ * Wrapper for the WCHAR configuration option
+ *
+ * We want to support platforms that do not provide `wchar_t`, so we
+ * sometimes have to disable providing wchar_t overloads through Catch2,
+ * e.g. the StringMaker specialization for `std::wstring`.
+ */
+
+#ifndef CATCH_CONFIG_WCHAR_HPP_INCLUDED
+#define CATCH_CONFIG_WCHAR_HPP_INCLUDED
+
+// We assume that WCHAR should be enabled by default, and only disabled
+// for a shortlist (so far only DJGPP) of compilers.
+
+#if defined(__DJGPP__)
+#  define CATCH_INTERNAL_CONFIG_NO_WCHAR
+#endif // __DJGPP__
+
+#if !defined( CATCH_INTERNAL_CONFIG_NO_WCHAR ) && \
+    !defined( CATCH_CONFIG_NO_WCHAR ) && \
+    !defined( CATCH_CONFIG_WCHAR )
+#    define CATCH_CONFIG_WCHAR
+#endif
+
+#endif // CATCH_CONFIG_WCHAR_HPP_INCLUDED

src/catch2/internal/catch_main.cpp

@@ -7,6 +7,7 @@
 // SPDX-License-Identifier: BSL-1.0
 #include <catch2/catch_session.hpp>
 #include <catch2/internal/catch_compiler_capabilities.hpp>
+#include <catch2/internal/catch_config_wchar.hpp>
 #include <catch2/internal/catch_leak_detector.hpp>
 #include <catch2/internal/catch_platform.hpp>