Looking at this makefile... why on earth are you building libcurl? It's on quite a few linux systems. The user is supposed to install the dependencies, except sometimes in the case of Windows...
Because you cant assume users have it.. unless you do a dynamic compile then its up to you to put the dll as a registered dll or in path of executable.
Take a look at the config for the build.. Then windows mingw makefile atleast. It strips out everything except the http get functionality.
Also it needs to be statically linked because I believe it is safer and avoids bugs where multi-threading could cause issues.. I believe this is why they went with the static
build for it.. was done before me.