Update stgdict.c

Co-authored-by: Bénédikt Tran <10796600+picnixz@users.noreply.github.com>

Author: ZeroIntensity

Modules/_ctypes/stgdict.c

@@ -383,7 +383,7 @@ PyCStructUnionType_update_stginfo(PyObject *type, PyObject *fields, int isStruct
         size = 0;
         align = 0;
         union_size = 0;
-        total_align = forced_alignment != 0 ? forced_alignment : 1;
+        total_align = forced_alignment == 0 ? 1 : forced_alignment;
         stginfo->ffi_type_pointer.type = FFI_TYPE_STRUCT;
         stginfo->ffi_type_pointer.elements = PyMem_New(ffi_type *, len + 1);
         if (stginfo->ffi_type_pointer.elements == NULL) {