Minor cleanup

Author: vitaut

src/os.cc

@@ -61,6 +61,7 @@
 
 namespace {
 #ifdef _WIN32
+
 // Return type of read and write functions.
 using rwresult = int;
 
@@ -69,20 +70,6 @@ using rwresult = int;
 inline unsigned convert_rwcount(size_t count) {
   return count <= UINT_MAX ? static_cast<unsigned>(count) : UINT_MAX;
 }
-#elif FMT_USE_FCNTL
-// Return type of read and write functions.
-using rwresult = ssize_t;
-
-inline auto convert_rwcount(size_t count) -> size_t { return count; }
-#endif
-}  // namespace
-
-FMT_BEGIN_NAMESPACE
-
-#ifdef _WIN32
-namespace detail {
-
-namespace {
 
 class system_message {
   system_message(const system_message&) = delete;
@@ -131,15 +118,25 @@ class utf8_system_category final : public std::error_category {
   }
 };
 
-}  // namespace
-
-}  // namespace detail
-
 FMT_API const std::error_category& system_category() noexcept {
   static const detail::utf8_system_category category;
   return category;
 }
 
+#elif FMT_USE_FCNTL
+
+// Return type of read and write functions.
+using rwresult = ssize_t;
+
+inline auto convert_rwcount(size_t count) -> size_t { return count; }
+
+#endif
+}  // namespace
+
+FMT_BEGIN_NAMESPACE
+
+#ifdef _WIN32
+
 std::system_error vwindows_error(int err_code, string_view format_str,
                                  format_args args) {
   auto ec = std::error_code(err_code, system_category());
@@ -166,6 +163,7 @@ void detail::format_windows_error(detail::buffer<char>& out, int error_code,
 void report_windows_error(int error_code, const char* message) noexcept {
   do_report_error(detail::format_windows_error, error_code, message);
 }
+
 #endif  // _WIN32
 
 buffered_file::~buffered_file() noexcept {