That doesn't make sense to me. If APR::UUID is a prereq, it should be listed in PREREQ_PM no matter what. If its already installed, whats the point of adding it to PREREQ_PM?
It's not supposed to make sense to you. Just run the Makefile.PL.:-)
The real answer is that the Makefile.PL requires different uuid generation module depending on the platform (win32/*nix) since there isn't on cross plaftorm module..except for APR::UUID. But I'm not going to require people to install APR just for that if they already have a one of the others installed. And if APR::UUID is available, there's no need to make any nother PREREQUS. Hense..the evals to see what is available.