when upgrading xorg-server from 1.7 to 1.9 from an binpkg, the protos don't get updated because they're not in RDEPEND. That causes compilation of x11-drivers/xf86-input-mouse-1.6.0 (and probably others) to fail because pkgconfig expects the newer protos. Reproducible: Always Steps to Reproduce:
On the other hand, xf86-input-mouse (and probably the other drivers, too) might also DEPEND on the appropriate protos. Generally speaking, DEPEND should be in sync with the .pc files. Not sure which way is the better solution here...
(Marking as a duplicate of a newer bug only because there's more analysis in the other bug.) Thanks for the report. *** This bug has been marked as a duplicate of bug 379545 ***