Make it into a standalone perl module? and use it; in the other ones? Maybe also see ExtUtils::Depends - Easily build XS extensions that depend on XS extensions
It's already a stand-alone perl module, sorry if that wasn't clear. "Use" simply does not drag anything into the Inline::C namespace -- I end up with an undefined symbol at runtime.
But ExtUtils::Depends looks like it should fit the bill, thanks.