Also curl_strequal. I think strcase.obj just wants removing from CURL_FROM_LIBCURL in winbuild/MakefileBuild.vc. (But maybe that would break buiiding with a static library or something.)
Anyway, these symbols are (the linker says) already in strcase.obj in libcurl.lib(libcurl.dll) and that causes the build to fail.
That looks like a correct fix, thanks!
winbuild: remove strcase.obj from curl build
Reported-by: Bruce Stephens