OpenSees linked with Tcl 8.6 (macos)

[userav]

The OpenSees macos binary available for download is linked to tcl8.5. For most use cases this is certainly ok, as macos sierra provides tcl8.5.9.

I have got a OpenSees/tcl script that makes use of tcl8.6 features (TclOO). So I would like to get OpenSees linked to tcl8.6.
I successfully installed tcl-tk 8.6 using homebrew (brew install tcl-tk).

Trying to compile OpenSees linking to tcl8.6 I get errors:
"commands.cpp:822:5: error: no matching function for call to 'Tcl_CreateCommand'
Tcl_CreateCommand(interp, "wipe", &wipeModel,"

I have previously compiled OpenSees with tcl8.6 on Linux and cygwin, so I don't expect a general problem linking it with tcl8.6.
Im Makefile.def I have tried to give the paths to the tcl8.6 installation. E.g:
"TCL_LIBRARY = /usr/local/opt/tcl-tk/lib/libtclstub8.6.a" (there is no libtcl8.6.a without stub?)
"C++FLAGS = ...... -D_TCL86"
"TCL_INCLUDES = -I/usr/local/opt/tcl-tk/include"
I used the default (clang) c and c++ compilers and gfortran (from brew install gcc).

Does anyone have a working Makefile.def for macos, linked to tcl8.6?