when a user updates sys-boot/syslinux using portage (e.g. from version 5.01 to 5.10) he/she maybe don't know that he/she has to take further actions like reinstalling the bootloader and to copy the new/updated modules from /usr/share/syslinux/*.c32 to /boot/syslinux for example to take the update into account.
Portage only adds syslinux to the system, but doesn't update any existing syslinux bootloader installations (not sure if the grub ebuild, which should have the same problem, does it better).
Add elog messages to tell the user about further required steps, which should only be displayed in case of an upgrade.
Not sure if we should just display a link to http://wiki.gentoo.org/wiki/Syslinux (and add a update section to the article) like we are doing it with other ebuilds (if we do that, this link could also be displayed after the user installed syslinux for the first time), which require further user actions.
There is no immediate action necessary. The old version of syslinux that is installed to /boot will continue to work, even if the syslinux package is updated.
There is already one upgrade message if you upgrade from the current stable version 4.06 to 5.10, per bug 447214.
It would really be helpful to at least give an elog message suggestion to run syslinux --update (or extlinux --update or ...). A syslinux update happens so rarely that a use (such as me) doesn’t remember the steps needed to do an upgrade.
Regarding the message for the >5 linking issue:
* it talks about the installation directory: make it clear that this is /boot (or some such) and not /usr/share/syslinux (where portage installs syslinux)
* when I do what the message says, I get:
# LD_LIBRARY_PATH="." ldd *.c32
ldd: warning: you do not have execution permission for `./ldlinux.c32'
It would be useful to have a pointer that makes it clear this is ok (I guess it is, as my system rebooted correctly)