Gentoo: emerge grub error - cat: /proc/mounts: No such file or directory

During my initial Gentoo installation, I ran into the following issue after trying to "emerge grub".

...
>>> Completed installing grub-0.96-r2 into /var/tmp/portage/grub-0.96-r2/image/

>>> Merging sys-boot/grub-0.96-r2 to /
cat: /proc/mounts: No such file or directory
cat: /proc/mounts: No such file or directory
*
* Cannot automatically mount your /boot partition.
* Your boot partition has to be mounted rw before the installation
* can continue. grub needs to install important files there.
*

!!! ERROR: sys-boot/grub-0.96-r2 failed.
!!! Function mount-boot_mount_boot_partition, Line 51, Exitcode 0
!!! Please mount your /boot partition manually!
!!! If you need support, post the topmost build error, NOT this status message.

!!! FAILED preinst: 1
livecd linux # grub
bash: grub: command not found

This thread over at Short-Media has exactly this error listed. However, that thread went nowhere and the user was redirected to search over at the Gentoo.org forums.

emerge grub fails (Jun 2004)
'emerge grub' fails (Jun 2004)
Grub wont compile. (Apr 2004)

Most posters indicate that you must run the following command prior to entering the chroot environment.

mount -t proc /proc /mnt/gentoo/proc

However, I can look back at my session logs and see that I already ran that particular command before entering the chroot. Oh, wait... no I did not run that particular command. (This is where using a terminal program like SecureCRT comes in handy.) This command should have been run just prior to entering the chroot environment. (See chapter 6 of the installation handbook.)

The fix should be as simple as:

livecd linux # cat /proc/mounts
cat: /proc/mounts: No such file or directory
livecd linux # exit
exit
livecd gentoo # mount -t proc none /mnt/gentoo/proc
livecd gentoo # chroot /mnt/gentoo /bin/bash
livecd / # env-update
>>> Regenerating /etc/ld.so.cache...
livecd / # source /etc/profile
livecd / # emerge grub