Over Here Daniel noted (channeling Stefan Kanthak)

The file "curl-7.58.0/projects/README" references

| Microsoft Internationalized Domain Name (IDN) Mitigation APIs:
| https://www.microsoft.com/en-us/download/details.aspx?id=734

This download is not available any more since quite some time
(almost 2 years, IIRC).