features: Map _ISOC2X_SOURCE to _ISOC23_SOURCE

Switch to the explicit version.

Signed-off-by: Keith Packard <[email protected]>

Author: keith-packard

newlib/libc/include/sys/features.h

@@ -89,9 +89,12 @@ extern "C" {
  * _ISOC11_SOURCE or gcc -std=c11 or g++ -std=c++11
  *	ISO C11
  *
- * _ISOC2x_SOURCE or gcc -std=c2x or g++ -std=c++20
+ * _ISOC2x_SOURCE or gcc -std=c2x or -std=c23 or g++ -std=c++20
  *	ISO C11
  *
+ * _ISOC23_SOURCE or gcc -std=c2x or -std=c2x or g++ -std=c++20
+ *	ISO C23
+ *
  * _ATFILE_SOURCE (implied by _POSIX_C_SOURCE >= 200809L)
  *	"at" functions
  *
@@ -122,8 +125,8 @@ extern "C" {
 #define	_ISOC99_SOURCE		1
 #undef _ISOC11_SOURCE
 #define	_ISOC11_SOURCE		1
-#undef _ISOC2X_SOURCE
-#define	_ISOC2X_SOURCE		1
+#undef _ISOC23_SOURCE
+#define	_ISOC23_SOURCE		1
 #undef _POSIX_SOURCE
 #define	_POSIX_SOURCE		1
 #undef _POSIX_C_SOURCE
@@ -255,10 +258,10 @@ extern "C" {
  *	g++ -std=c++11 or newer (on by default since GCC 6), or with
  *	_ISOC11_SOURCE.
  *
- * __ISO_C_VISIBLE >= 2020
- *	ISO C2x; enabled with gcc -std=c2x or newer,
+ * __ISO_C_VISIBLE >= 2023
+ *	ISO C23; enabled with gcc -std=c23 or -std=c2x or newer,
  *	g++ -std=c++20 or newer, or with
- *	_ISOC2X_SOURCE.
+ *	_ISOC2X_SOURCE or _ISOC23_SOURCE.
  *
  * __ATFILE_VISIBLE
  *	"at" functions; enabled by default, with _ATFILE_SOURCE,
@@ -318,9 +321,15 @@ extern "C" {
 #define __ZEPHYR_VISIBLE        0
 #endif
 
-#if defined(_ISOC2X_SOURCE) || \
+#ifdef _ISOC2X_SOURCE
+#undef _ISOC2X_SOURCE
+#undef _ISOC23_SOURCE
+#define _ISOC23_SOURCE      1
+#endif
+
+#if defined(_ISOC23_SOURCE) ||                                          \
   (__STDC_VERSION__ - 0) > 201710L || (__cplusplus - 0) >= 202002L
-#define __ISO_C_VISIBLE		2020
+#define __ISO_C_VISIBLE		2023
 #elif defined(_ISOC11_SOURCE) || \
   (__STDC_VERSION__ - 0) >= 201112L || (__cplusplus - 0) >= 201103L
 #define	__ISO_C_VISIBLE		2011