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

Calculating dependencies ... done!
Dependency resolution took 0.82 s (backtrack: 0/20).


!!! All ebuilds that could satisfy "=net-libs/libnsl-0-r2" have been masked.
!!! One of the following masked packages is required to complete your request:
- net-libs/libnsl-0-r2::gentoo (masked by: package.mask)
/Volumes/Disk 1/Repository/portage-git/profiles/package.mask:
# Andreas K. Hüttel <dilfridge@gentoo.org> (2018-09-11)
# Mask transition ebuilds that were needed only for <glibc-2.26
# We will keep them in the tree as long as we have masked
# <glibc-2.26.


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