zend_portability: Add ZEND_CONTAINER_OF()

Author: TimWolla

UPGRADING.INTERNALS

@@ -98,6 +98,7 @@ PHP 8.6 INTERNALS UPGRADE NOTES
     the non-throw versions.
   . The XtOffsetOf() alias of C’s offsetof() macro has been removed. Use
     offsetof() directly.
+  . Added ZEND_CONTAINER_OF().
 
 ========================
 2. Build system changes

Zend/zend_portability.h

@@ -385,6 +385,8 @@ char *alloca();
 #define ZEND_ELEMENT_COUNT(m)
 #endif
 
+#define ZEND_CONTAINER_OF(ptr, Type, member) ((Type*)((char*)(1 ? (ptr) : &((Type*)0)->member) - offsetof(Type, member)))
+
 #ifdef HAVE_BUILTIN_CONSTANT_P
 # define ZEND_CONST_COND(_condition, _default) \
 	(__builtin_constant_p(_condition) ? (_condition) : (_default))