Pass pointer to (char*) instead of (zend_string*) to spprintf

I don't believe these error messages have any unit tests covering them.
Some may be unreachable in practice.

This might not be comprehensive - I didn't test other files.

```
struct _zend_class_entry {
	char type;
	zend_string *name;
```

v8js_object_export.cc

@@ -496,7 +496,7 @@ static void v8js_fake_call_impl(const v8::FunctionCallbackInfo<v8::Value>& info)
 	if (info.Length() < 2) {
 		error_len = spprintf(&error, 0,
 			"%s::__call expects 2 parameters, %d given",
-			ce->name, (int) info.Length());
+			ZSTR_VAL(ce->name), (int) info.Length());
 
 		if (error_len > std::numeric_limits<int>::max()) {
 			zend_throw_exception(php_ce_v8js_exception,
@@ -535,7 +535,7 @@ static void v8js_fake_call_impl(const v8::FunctionCallbackInfo<v8::Value>& info)
 		// in the Function->Call method below is a (signed) int.
 		error_len = spprintf(&error, 0,
 			"%s::__call expects fewer than a million arguments",
-			ce->name);
+			ZSTR_VAL(ce->name));
 
 		if (error_len > std::numeric_limits<int>::max()) {
 			zend_throw_exception(php_ce_v8js_exception,
@@ -555,8 +555,8 @@ static void v8js_fake_call_impl(const v8::FunctionCallbackInfo<v8::Value>& info)
 	if (str.IsEmpty())
 	{
 		error_len = spprintf(&error, 0,
-			"%s::__call expect 1st parameter to be valid function name, toString() invocation failed.",
-			ce->name);
+			"%s::__call expects 1st parameter to be valid function name, toString() invocation failed.",
+			ZSTR_VAL(ce->name));
 
 		if (error_len > std::numeric_limits<int>::max()) {
 			zend_throw_exception(php_ce_v8js_exception,
@@ -584,7 +584,7 @@ static void v8js_fake_call_impl(const v8::FunctionCallbackInfo<v8::Value>& info)
 		(method_ptr->common.fn_flags & ZEND_ACC_PUBLIC) == 0 ||
 		(method_ptr->common.fn_flags & (ZEND_ACC_CTOR|ZEND_ACC_DTOR)) != 0) {
 		error_len = spprintf(&error, 0,
-			"%s::__call to %s method %s", ce->name,
+			"%s::__call to %s method %s", ZSTR_VAL(ce->name),
 			(method_ptr == NULL) ? "undefined" : "non-public", method_name);
 
 		if (error_len > std::numeric_limits<int>::max()) {