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 "=llvm-runtimes/libgcc-19.1.7" have been masked.
!!! One of the following masked packages is required to complete your request:
- llvm-runtimes/libgcc-19.1.7::gentoo (masked by: package.mask)
/Volumes/Disk 1/Repository/portage-git/profiles/default/linux/package.mask:
# Michal Rostecki <vadorovsky@protonmail.com> (2025-02-10)
# A libgcc_s drop-in replacement, which conflicts with sys-devel/gcc,
# therefore meant only for profiles which can work without GCC being
# present even as a fallback.


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