Hi,

I previously reported that json-c.pc seems incorrect.
- https://cygwin.com/pipermail/cygwin/2023-August/254350.html

The modified version of json-c.cygport and its CI results are shown below.
- cygport
  - https://cygwin.com/cgit/cygwin-packages/playground/commit/?id=42b2343c88e9ba85dd689579335a77776691bb27
- CI
  - https://github.com/cygwin/scallywag/actions/runs/6286740463

Patch is also attached.