Merge pull request #3787 from stevenjohnstone/bug/3768

Avoid undefined int overflow behaviour

Author: kddnewton

templates/src/serialize.c.erb

@@ -315,7 +315,7 @@ pm_serialize_content(pm_parser_t *parser, pm_node_t *node, pm_buffer_t *buffer)
                 // buffer offset. We will add a leading 1 to indicate that this
                 // is a buffer offset.
                 uint32_t content_offset = pm_sizet_to_u32(buffer->length);
-                uint32_t owned_mask = (uint32_t) (1 << 31);
+                uint32_t owned_mask = 1U << 31;
 
                 assert(content_offset < owned_mask);
                 content_offset |= owned_mask;