Support C23 typeof operator

The 'typeof' operator, originally a GNU extension, is now part of the
C23 standard. This change enables its use in list macros where
supported.

Change-Id: I6a6e4e0caa4b72f16d957e0bd87722fac1915e3d

Author: jserv

list.h

@@ -1,4 +1,4 @@
-/* Linux-like doubly-linked list implementation */
+/* Linux-like circular doubly-linked list implementation */
 
 #pragma once
 
@@ -8,10 +8,16 @@ extern "C" {
 
 #include <stddef.h>
 
-/* "typeof" is a GNU extension.
+/**
+ * Feature detection for 'typeof':
+ * - Supported as a GNU extension in GCC/Clang.
+ * - Part of C23 standard (ISO/IEC 9899:2024).
+ *
  * Reference: https://gcc.gnu.org/onlinedocs/gcc/Typeof.html
  */
-#if defined(__GNUC__) || defined(__clang__)
+#if defined(__GNUC__) || defined(__clang__) ||         \
+    (defined(__STDC__) && defined(__STDC_VERSION__) && \
+     (__STDC_VERSION__ >= 202311L)) /* C23 ?*/
 #define __LIST_HAVE_TYPEOF 1
 #endif
 

scripts/checksums

@@ -1,3 +1,3 @@
 db6784ff3917888db4d1dceaa0570d99ed40e762  queue.h
-bfb6df45d64356868c86a7173455d39970bd0270  list.h
+63d8b3bcc12c521926893e0b71f0ffdfd0bbc8ca  list.h
 3bb0192cee08d165fd597a9f6fbb404533e28fcf  scripts/check-commitlog.sh