When writing a CPAN module, how do I declare a dependency on syscall.ph and get it built automatically if it is lacking?

Recently I was attempting to install Fuse but it just wouldn't pass tests. Eventually I began manually debugging the test suite and it turned on an "optional" use of syscall.ph. On a lark I read the docs for h2ph and ran ( cd /usr/include; h2ph -r -l . ) after which all the tests passed. Fuse didn't declare syscall.ph as a dependency and perhaps it isn't for some people. It was for me. I'd like to patch it appropriately so the normal CPAN infrastructure will go build this stuff automatically.