Convert resources to objects in ext/zlib

Closes GH-5680

Author: kocsismate

UPGRADING

@@ -440,7 +440,7 @@ PHP 8.0 UPGRADE NOTES
 
 - Sysvmsg:
   . msg_get_queue() will now return an SysvMessageQueue object rather than a
-    resource.  Return value checks using is_resource() should be replaced with
+    resource. Return value checks using is_resource() should be replaced with
     checks for `false`.
 
 - Sysvsem:
@@ -474,6 +474,12 @@ PHP 8.0 UPGRADE NOTES
 
 - Zlib:
   . gzgetss() has been removed.
+  . inflate_init() will now return an InflateContext object rather than a
+    resource. Return value checks using is_resource() should be replaced with
+    checks for `false`.
+  . deflate_init() will now return a DeflateContext object rather than a
+    resource. Return value checks using is_resource() should be replaced with
+    checks for `false`.
 
 ========================================
 2. New Features

ext/zlib/php_zlib.h

@@ -47,6 +47,7 @@ typedef struct _php_zlib_context {
 	int status;
 	size_t inflateDictlen;
 	php_zlib_buffer buffer;
+	zend_object std;
 } php_zlib_context;
 
 ZEND_BEGIN_MODULE_GLOBALS(zlib)