science/hdf5 should be upgraded to 1.12, but some ports are not compatible with this version, and it has been suggested to repocopy the actual port to science/hdf5-110. PR 251894 proposes a patch to do that, and an exp-run has been launched to detect the incompatibilities. Unfortunately, your port science/chemps2 failed: see http://package18.nyi.freebsd.org/data/121amd64-default-foo/2021-01-20_21h30m48s/logs/errors/CheMPS2-1.8.9_6.log Could you please propose a patch, either to fix it with 1.12 or to switch to hdf5-110?
1.8.10 should build fine with HDF5 1.12.
A commit references this bug: Author: yuri Date: Mon Feb 1 09:53:55 UTC 2021 New revision: 563561 URL: https://svnweb.freebsd.org/changeset/ports/563561 Log: science/chemps2: Update 1.8.9 -> 1.8.10 PR: 252969 Changes: head/science/chemps2/Makefile head/science/chemps2/distinfo head/science/chemps2/pkg-plist