dev-libs/openssl:0.9.8 does not provide any headers, but satisfies the dependency "ssl? ( >=dev-libs/openssl-0.9.7[kerberos?] )". Compilation will fail without dev-libs/openssl:0 installed. This should be done in a revbump, otherwise it can break things depending on activation of dynamic-deps or PM choice.
Since taking over maintainership of lighttpd it appears someone else beat me to the punch and it's already fixed. Thanks to whoever did that work! Closing the bug as fixed. Please re-open if the dependencies still aren't correct.