"The AI_ADDRCONFIG flag is defined on the Windows SDK for Windows Vista and later. The AI_ADDRCONFIG flag is supported on Windows Vista and later." https://docs.microsoft.com/en-us/windows/desktop/api/ws2tcpip/nf-ws2tcpip-getaddrinfo
However, the version of MinGW we use on Travis is not current and does not carry the relevant definition, as such I defined it in compat. https://github.com/wine-mirror/wine/blob/master/include/ws2tcpip.h
Testing confirms that the PROTECTION_LEVEL_UNRESTRICTED and IPV6_PROTECTION_LEVEL are now supported by the version of windows that we test against, so can be removed. https://travis-ci.org/bitcoin/bitcoin/jobs/483255439