Those are the CORE Perl include files that your script is including. This should be discussed in the docs for the compiler, I'm sure, but you should add the path to those include files as a -I arg to cc. You *should* have those files. Look around in @INC to try and find them. They'll be in something like

    /usr/lib/perl5/<arch>/<version>/CORE
[download]

where <arch> is your architecture, and <version> is your Perl version.

So you'd do something like

    % cc -I /usr/lib/perl5/<arch>/<version>/CORE fred.c
[download]

I think.