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

Calculating dependencies ...

!!! Problem resolving dependencies for =dev-libs/tre-0.8.0_p20210321-r4
 done!
Dependency resolution took 0.83 s (backtrack: 0/20).


!!! The ebuild selected to satisfy "=dev-libs/tre-0.8.0_p20210321-r4" has unmet requirements.
- dev-libs/tre-0.8.0_p20210321-r4::gentoo USE="agrep alloca approx nls python -debug -profile" PYTHON_TARGETS="-python3_12"

  The following REQUIRED_USE flag constraints are unsatisfied:
    python? ( python_targets_python3_12 )

  The above constraints are a subset of the following complete expression:
    agrep? ( approx ) python? ( any-of ( python_targets_python3_12 ) )