These are the packages that would be merged, in order:

Calculating dependencies ... done!
Dependency resolution took 0.83 s (backtrack: 0/20).


!!! All ebuilds that could satisfy "=dev-embedded/avr-libc-2.1.0" have been masked.
!!! One of the following masked packages is required to complete your request:
- dev-embedded/avr-libc-2.1.0::gentoo (masked by: package.mask)
/Volumes/Disk 1/Repository/portage-git/profiles/package.mask:
# Diego E. Pettenò <flameeyes@gentoo.org> (2009-01-03)
# These packages are not supposed to be merged directly, instead
# please use sys-devel/crossdev to install them.


For more information, see the MASKED PACKAGES section in the emerge
man page or refer to the Gentoo Handbook.