Without seeing the package’s build log, it’s impossible to say what specifically is wrong. Try cpanm -v and/or cat'ing the log file that the build refers to.
As can be seen from a snapshot of a Windows builder, it does have a libcurl and its headers installed as a Chocolatey package. Maybe some compiler switches or other envvars are needed for Strawberry Perl to find that library or something else that it needs.