Disclaimer: this bug has been filed in a semi-automated manner.
When emerging the package sys-boot/grub-0.97-r12, the following elog messages are displayed:
* To avoid automounting and auto(un)installing with /boot,
* just export the DONT_MOUNT_BOOT variable.
Such messages should only be displayed when the package is a new install.
These situations can be checked in the ebuild as follows:
if ! has_version 'sys-boot/grub'; then
See the tracker bug 440214 for more details.
Messaging could be made less verbose but since the grub:0 package exists now only to help maintain systems that haven't or can't easily migrate to another bootloader, these changes aren't going to be integrated.