Fix MSVC level 1 (severe) warnings

We fix (hopefully) all instances of:

* <https://docs.microsoft.com/en-us/cpp/error-messages/compiler-warnings/compiler-warning-level-1-c4005>
* <https://docs.microsoft.com/en-us/cpp/error-messages/compiler-warnings/compiler-warning-level-1-c4024>
* <https://docs.microsoft.com/en-us/cpp/error-messages/compiler-warnings/compiler-warning-level-1-c4028>
* <https://docs.microsoft.com/en-us/cpp/error-messages/compiler-warnings/compiler-warning-level-1-c4047>
* <https://docs.microsoft.com/en-us/cpp/error-messages/compiler-warnings/compiler-warning-level-1-c4087>
* <https://docs.microsoft.com/en-us/cpp/error-messages/compiler-warnings/compiler-warning-level-1-c4090>
* <https://docs.microsoft.com/en-us/cpp/error-messages/compiler-warnings/compiler-warning-level-1-c4273>
* <https://docs.microsoft.com/en-us/cpp/error-messages/compiler-warnings/compiler-warning-level-1-c4312>

`zend_llist_add_element()` and `zend_llist_prepend_element()` now
explicitly expect a *const* pointer.

We use the macro `ZEND_VOIDP()` instead of a `(void*)` cast to suppress
C4090; this should prevent accidential removal of the cast by
clarifying the intention, and makes it easier to remove the casts if
the issue[1] will be resolved sometime.

[1] <https://developercommunity.visualstudio.com/content/problem/390711/c-compiler-incorrect-propagation-of-const-qualifie.html>

1 files changed, 3 insertions, 3 deletions

diff --git a/ext/com_dotnet/com_handlers.c b/ext/com_dotnet/com_handlers.c
index e6434e52cf..4ff80d96e9 100644
--- a/ext/com_dotnet/com_handlers.c
+++ b/ext/com_dotnet/com_handlers.c
@@ -177,7 +177,7 @@ static void com_write_dimension(zend_object *object, zval *offset, zval *value)
 	}
 }
 
-static zval *com_get_property_ptr_ptr(zval *object, zval *member, int type, void **cache_slot)
+static zval *com_get_property_ptr_ptr(zend_object *object, zend_string *member, int type, void **cache_slot)
 {
 	return NULL;
 }
@@ -224,10 +224,10 @@ static HashTable *com_properties_get(zend_object *object)
 	 * infinite recursion when the hash is displayed via var_dump().
 	 * Perhaps it is best to leave it un-implemented.
 	 */
-	return &zend_empty_array;
+	return (HashTable *) &zend_empty_array;
 }
 
-static HashTable *com_get_gc(zval *object, zval **table, int *n)
+static HashTable *com_get_gc(zend_object *object, zval **table, int *n)
 {
 	*table = NULL;
 	*n = 0;