Parser: draft fix for struct compound literal init (issue #299)

Investigated the bug where compound literals like
(struct point){10, 20, 30} produced shifted field values
(e.g., x got garbage, y=10, z=20). Added a temporary fix
by adjusting the source address +4 bytes in parser.c.

Tested with simple cases: x=10, y=20, z=30. This is an
experimental patch; needs review for design correctness.

Refs: #299

Author: lorettayao