Log Message:
Update to fehQlibs-15 (as fehqlibs-0.9.15). From the changelog:

- Added the Guninski patch for alloc from Qualys (CVE-2005-1513).
- dns_ipq (IP qualify) now with unified IPv4/IPv6 handling and evaluation
  of DNS well-know names 'localhost' and 'ipv[4|6]-loopback' (RFC 6761).
- Fixed DNS lookup for IPv6 addresses. Adjusted DNS man pages.

Bump default BUILDLINK_API_DEPENDS, as all fehware requires this version.