Fix libxml2 2.12 build due to API breaks

See https://github.com/php/php-src/actions/runs/7062192818/job/19225478601

Author: nielsdos

ext/libxml/libxml.c

@@ -472,7 +472,11 @@ static void _php_libxml_free_error(void *ptr)
 	xmlResetError((xmlErrorPtr) ptr);
 }
 
-static void _php_list_set_error_structure(xmlErrorPtr error, const char *msg)
+#if LIBXML_VERSION >= 21200
+static void _php_list_set_error_structure(const xmlError *error, const char *msg)
+#else
+static void _php_list_set_error_structure(xmlError *error, const char *msg)
+#endif
 {
 	xmlError error_copy;
 	int ret;
@@ -725,7 +729,11 @@ PHP_LIBXML_API void php_libxml_ctx_warning(void *ctx, const char *msg, ...)
 	va_end(args);
 }
 
+#if LIBXML_VERSION >= 21200
+PHP_LIBXML_API void php_libxml_structured_error_handler(void *userData, const xmlError *error)
+#else
 PHP_LIBXML_API void php_libxml_structured_error_handler(void *userData, xmlErrorPtr error)
+#endif
 {
 	_php_list_set_error_structure(error, NULL);
 
@@ -957,11 +965,9 @@ PHP_FUNCTION(libxml_use_internal_errors)
 /* {{{ Retrieve last error from libxml */
 PHP_FUNCTION(libxml_get_last_error)
 {
-	xmlErrorPtr error;
-
 	ZEND_PARSE_PARAMETERS_NONE();
 
-	error = xmlGetLastError();
+	const xmlError *error = xmlGetLastError();
 
 	if (error) {
 		object_init_ex(return_value, libxmlerror_class_entry);

ext/soap/php_sdl.c

@@ -332,7 +332,7 @@ static void load_wsdl_ex(zval *this_ptr, char *struri, sdlCtx *ctx, int include)
 	sdl_restore_uri_credentials(ctx);
 
 	if (!wsdl) {
-		xmlErrorPtr xmlErrorPtr = xmlGetLastError();
+		const xmlError *xmlErrorPtr = xmlGetLastError();
 
 		if (xmlErrorPtr) {
 			soap_error2(E_ERROR, "Parsing WSDL: Couldn't load from '%s' : %s", struri, xmlErrorPtr->message);