forum.freeciv.org

As far as I can tell, I've installed everything needed, and I can find all of the (immediate) dependencies of ws2tcpip.h, but I get this error consistently when running autoconf or configure.

checking ws2tcpip.h usability... no
checking ws2tcpip.h presence... yes
configure: WARNING: ws2tcpip.h: present but cannot be compiled
configure: WARNING: ws2tcpip.h: check for missing prerequisite headers?
configure: WARNING: ws2tcpip.h: see the Autoconf documentation
configure: WARNING: ws2tcpip.h: section "Present But Cannot Be Compiled"
configure: WARNING: ws2tcpip.h: proceeding with the compiler's result
configure: WARNING: ## ------------------------------------------------------------- ##
configure: WARNING: ## Report this to https://www.hostedredmine.com/projects/freeciv ##
configure: WARNING: ## ------------------------------------------------------------- ##
checking for ws2tcpip.h... no

At a guess I figure it might be trying to #include from the wrong directory tree.
I've got copies of the file in these directories:
C:\cygwin64\usr\include\w32api
C:\cygwin64\usr\i686-w64-mingw32\sys-root\mingw\include
C:\cygwin64\usr\x86_64-w64-mingw32\sys-root\mingw\include

Any ideas?

See config.log for the exact error it gets when making the ws2tcpip.h test.

It's years since I built freeciv on cygwin myself. For Windows builds I've been mainly using msys2
http://forum.freeciv.org/f/viewtopic.php?f=14&t=75398