remove pre-C++20 work-arounds

modules/c++/coda_oss/include/coda_oss/string.h

@@ -21,47 +21,11 @@
  */
 
 #pragma once
-#ifndef CODA_OSS_coda_oss_string_h_INCLUDED_
-#define CODA_OSS_coda_oss_string_h_INCLUDED_
 
 #include <string>
 
-#include "coda_oss/CPlusPlus.h"
-
-// This logic needs to be here rather than <std/string> so that `coda_oss::u8string` will
-// be the same as `std::u8string`.
-#ifndef CODA_OSS_HAVE_std_u8string_
-    #define CODA_OSS_HAVE_std_u8string_ 0  // assume no std::u8string
-#endif
-#if CODA_OSS_cpp20
-    #if defined(__cpp_lib_char8_t)  // https://en.cppreference.com/w/cpp/feature_test
-        #undef CODA_OSS_HAVE_std_u8string_
-        #define CODA_OSS_HAVE_std_u8string_ 1
-    #endif
-#endif // CODA_OSS_cpp20
-
-#include "config/compiler_extensions.h"
-
 namespace coda_oss
 {
-    // char8_t for UTF-8 characters
-    CODA_OSS_disable_warning_push
-    #if _MSC_VER
-    #pragma warning(disable: 5052) // Keyword '...' was introduced in C++20 and requires use of the '...' command-line option
-    #endif
-
-    #if !defined(__cpp_char8_t) // https://en.cppreference.com/w/cpp/feature_test
-        enum class char8_t : unsigned char { }; // https://en.cppreference.com/w/cpp/language/types
-    #elif CODA_OSS_HAVE_std_u8string_
-       // `char8_t` is a keyword in C++20
-    #endif
-    #if CODA_OSS_HAVE_std_u8string_
-        using u8string = std::u8string;
-    #else
-        using u8string = std::basic_string<char8_t>; // https://en.cppreference.com/w/cpp/string
-    #endif
-
-    CODA_OSS_disable_warning_pop
+	using std::u8string;
 }
 
-#endif  // CODA_OSS_coda_oss_string_h_INCLUDED_

modules/c++/std/include/std/cstddef

@@ -19,9 +19,5 @@
  *
  */
 #pragma once 
-#ifndef CODA_OSS_std_cstddef_INCLUDED_
-#define CODA_OSS_std_cstddef_INCLUDED_
 
-#include <cstddef>
-
-#endif  // CODA_OSS_std_cstddef_INCLUDED_
+#include "coda_oss/cstddef.h"

modules/c++/std/include/std/filesystem

@@ -19,10 +19,6 @@
  *
  */
 #pragma once
-#ifndef CODA_OSS_std_filesystem_INCLUDED_
-#define CODA_OSS_std_filesystem_INCLUDED_
 
 #include <filesystem>
 #include "sys/filesystem.h"
-
-#endif  // CODA_OSS_std_filesystem_INCLUDED_

modules/c++/std/include/std/memory

@@ -19,9 +19,5 @@
  *
  */
 #pragma once
-#ifndef CODA_OSS_std_memory_INCLUDED_
-#define CODA_OSS_std_memory_INCLUDED_
 
 #include <memory>
-
-#endif  // CODA_OSS_std_memory_INCLUDED_

modules/c++/std/include/std/optional

@@ -19,9 +19,6 @@
  *
  */
 #pragma once 
-#ifndef CODA_OSS_std_optional_INCLUDED_
-#define CODA_OSS_std_optional_INCLUDED_
 
 #include "coda_oss/optional.h"
 
-#endif  // CODA_OSS_std_optional_INCLUDED_

modules/c++/std/include/std/string

@@ -19,34 +19,5 @@
  *
  */
 #pragma once
-#ifndef CODA_OSS_std_string_INCLUDED_
-#define CODA_OSS_std_string_INCLUDED_
 
-#include <string>
 #include "coda_oss/string.h"
-
-// Make it (too?) easy for clients to get our various std:: implementations
-#ifndef CODA_OSS_NO_std_u8string
-    #if CODA_OSS_HAVE_std_u8string_ // set in coda_oss/string.h
-        #define CODA_OSS_NO_std_u8string 1  // no need to muck with `std`
-    #else
-        #define CODA_OSS_NO_std_u8string 0  // use our own
-    #endif
-#endif
-
-#if !CODA_OSS_NO_std_u8string
-#include "config/compiler_extensions.h"
-namespace std // This is slightly uncouth: we're not supposed to augment "std".
-{
-    CODA_OSS_disable_warning_push
-    #if defined(_MSC_VER) && (_MSC_VER >= 1927)
-    #pragma warning(disable: 5052) // Keyword '...' was introduced in C++ 20 and requires use of the '...' command-line option
-    #endif
-    using char8_t = coda_oss::char8_t;
-    CODA_OSS_disable_warning_pop
-
-    using coda_oss::u8string;
-}
-#endif // !CODA_OSS_NO_std_u8string
-
-#endif  // CODA_OSS_std_string_INCLUDED_

modules/c++/std/include/std/type_traits

@@ -19,10 +19,7 @@
  *
  */
 #pragma once
-#ifndef CODA_OSS_std_type_traits_INCLUDED_
-#define CODA_OSS_std_type_traits_INCLUDED_
 
-#include <type_traits>
+#include "coda_oss/type_traits.h"
 
-#endif  // CODA_OSS_std_type_traits_INCLUDED_