We should add some code to the initscript to check if /dev/random is empty and warn users to remerge apr with USE=random or install rng-tools. We just need to check if /proc/sys/kernel/random/entropy_avail is 0 or not. Remember to ask all archs to check this as /proc changes between archs.
It doesn't need to be 0. apache2 takes ages (around 5 minutes to be exact) to start when the entropy_avail is less than around 1000 (that's with mod_ssl and subversion enabled). Usage of entropy bits varies between setups (whenever mod_ssl is enabled, or not, whenever apr was buil with +urandom USE). IMVHO adding such code to init script is pointless, better to add big, fat warning in pkg_postinst about using rng-tools (or building apr with +urandom) if apache starts slowly.
you'll only need entropy with mod_auth_digest, so this is very setup dependant... as stated in comment #1 even a check for >= 0 is nearly pointless.. if you rely on auth_digest, put urandom in your use flags and re-emerge apr, or use tools like clrngd or rng-tools...