devel/yyjson: Improve port and enable 'make test'
- Switch to DISTVERSION as per Porters Handbook
- Define LICENSE_FILE
- Enable unit tests (make test) Backport upstream patch 878d5da9b6c0352c2601bd6c244c0ef994ee1c24
Reference:
https://github.com/ibireme/yyjson/commit/878d5da9b6c0352c2601bd6c244c0ef994ee1c24
PR: 288934
Approved by: pkubaj (maintainer, previous iteration)