INDEX-13 fails to build after removal of wxgtk28

Hello,

after the removal of wxgtk28 (commit 
ba3f1e00370d69b693977b156905673d6ca1f07c), I can no longer build the INDEX:

----8<----
Generating INDEX-13 - please wait..--- describe.accessibility ---
--- describe.arabic ---
--- describe.archivers ---
--- describe.astro ---
--- describe.audio ---
--- describe.benchmarks ---
--- describe.biology ---
--- describe.cad ---
make[4]: "/usr/ports/Mk/bsd.wx.mk" line 309: String comparison operator 
must be either == or !=
make[4]: "/usr/ports/Mk/bsd.wx.mk" line 309: String comparison operator 
must be either == or !=
make[4]: "/usr/ports/Mk/bsd.wx.mk" line 401: Malformed conditional 
(${_WX_VER} == 3.2)
make[4]: Fatal errors encountered -- cannot continue
===> cad/basicdsp failed
*** [describe.cad] Error code 1

make[1]: stopped in /usr/ports
1 error

make[1]: stopped in /usr/ports

********************************************************************
Before reporting this error, verify that you are running a supported
version of FreeBSD (see https://www.FreeBSD.org/ports/) and that you
have a complete and up-to-date ports collection.  (INDEX builds are
not supported with partial or out-of-date ports collections.
If that is the case, then
report the failure to ports@FreeBSD.org together with relevant
details of your ports configuration (including FreeBSD version,
your architecture, your environment, and your /etc/make.conf
settings, especially compiler flags and OPTIONS_SET/UNSET settings).

Note: the latest pre-generated version of INDEX may be fetched
automatically with "make fetchindex".
********************************************************************

*** Error code 1

Stop.
make: stopped in /usr/ports
--->8----

This also happens with a freshly checked out ports tree.

The line numbers make is complaining about haven't been touched. I don't 
see what's wrong.

Anyone else seeing this? Any hints on what could be the issue?

Thanks
Philipp