php#57: Fix C++ compilation error in zend_async_API.h for ICU/intl extension

       The flexible array member `data[]` in struct _zend_async_waker_trigger_s
       causes MSVC C4200 warning when compiling C++ files (intl_convertcpp.cpp).
       C++ doesn't standardize flexible arrays until C++23, treating them as
       nonstandard extension.

       Changes:
       - Add conditional compilation for C++ compatibility in struct definition
       - Adjust memory allocation logic to account for different sizeof() behavior
       - Preserve optimal C99 flexible array semantics for C compilation

       Fixes compilation error when building intl extension with MSVC /WX flag.

Author: EdmondDantes

Zend/zend_async_API.c

@@ -479,8 +479,15 @@ static zend_always_inline zend_async_waker_trigger_t *waker_trigger_create(
 		initial_capacity = 2;
 	}
 
+#ifdef __cplusplus
+	// Account for the [1] element already included in sizeof()
+	size_t total_size = sizeof(zend_async_waker_trigger_t)
+			+ (initial_capacity - 1) * sizeof(zend_async_event_callback_t *);
+#else
+	// Flexible array member doesn't contribute to sizeof()
 	size_t total_size = sizeof(zend_async_waker_trigger_t)
 			+ initial_capacity * sizeof(zend_async_event_callback_t *);
+#endif
 	zend_async_waker_trigger_t *trigger = (zend_async_waker_trigger_t *) emalloc(total_size);
 
 	trigger->length = 0;

Zend/zend_async_API.h

@@ -430,7 +430,12 @@ struct _zend_async_waker_trigger_s {
 	uint32_t length; /* current number of callbacks */
 	uint32_t capacity; /* allocated slots in the array */
 	zend_async_event_t *event;
-	zend_async_event_callback_t *data[]; /* flexible array member */
+	/* C++ compatibility fix for ICU/intl extension: flexible arrays not standard in C++ */
+#ifdef __cplusplus
+	zend_async_event_callback_t *data[1]; /* C++ compatible array */
+#else
+	zend_async_event_callback_t *data[]; /* C99 flexible array member */
+#endif
 };
 
 /* Dynamic array of async event callbacks with single iterator protection */