Kalzium build fails (part of KDE4 port upgrade)

[Dave]

portupgrade kalzium

...

[ 48%] Generating parser.cmx
[ 49%] Generating datastruct.cmx
[ 50%] Generating chem.cmi
[ 51%] Generating lexer.cmx
[ 51%] Generating chem.cmx
File "/usr/ports/science/kalzium/work/kalzium-4.12.5/src/solver/chem.ml", line 1:
Error: /usr/local/lib/ocaml/facile/facile.cmi
is not a compiled interface for this version of OCaml.
It seems to be for an older version of OCaml.
*** [src/chem.cmx] Error code 2
1 error
*** [src/CMakeFiles/kalzium.dir/all] Error code 2

...

uname -a
FreeBSD amd.asgard.uk 9.2-RELEASE-p5 FreeBSD 9.2-RELEASE-p5 #0: Tue Apr 29 
19:09:13 UTC 2014     root at amd64-builder.daemonology.net:/usr/obj/usr/src/sys/GENERIC  
amd64