Upgrading PHP breaks eAccelerator build (because PHP version is hard-encoded in eAccelerator shared object file).
The eBuild for eAccelerator should take this into consideration and contain some dependecies.
Steps to Reproduce:
1. Upgrade php (while having eAccerlator not rebuilt)
2. Restart your webserver (e.g. Apache)
eAccelerator start fails and complains about "wrong" php version.
eAccelerator eBuild should depend on php version and hard-rebuild should be taken into consideration.
Portage cannot forcibly re-emerge any package due to another package being upgraded. This might be on the TODO list for future portage-versions but currently this is not implemented.
*** This bug has been marked as a duplicate of bug 192319 ***