The php4 extensions is broken if installed both php4 both php5. Reproducible: Always Steps to Reproduce: 1. emerge =php-4* =php-5* 2. emerge dev-php4/eaccelerator 3. eAccelerator ebuild use the php-5 libs :-( Actual Results: If php5 installed then the portage merging the php4 extensions for php5 libs.
Honestly, I don't care. We are only still shipping php-4* as upstream has not officially given up on it yet (whatever you think about it; it's hardmasked for a reason). I'm marking the bug as LATER as this might be the same for php5 vs php6.