ports/INDEX building broken on 11.0-CURRENT

Please excuse the crosspost.  I'm not sure if this is a ports problem or
a CURRENT problem.

I just updated my 11.0-CURRENT machine to r265940 and can no longer
build ports/INDEX-11.  My ports tree is r353903.  I think this problem
is being caused by the recent changes to /usr/share/mk/*.

# make index
Generating INDEX-11 - please wait..--- describe.accessibility ---
--- describe.arabic ---
--- describe.archivers ---
--- describe.astro ---
--- describe.audio ---
--- describe.benchmarks ---
--- describe.biology ---
--- describe.cad ---
--- describe.chinese ---
--- describe.comms ---
--- describe.converters ---
--- describe.databases ---
--- describe.deskutils ---
--- describe.devel ---
clang33: not found
make[5]: "/usr/share/mk/bsd.compiler.mk" line 24: warning: "clang33 --version" returned non-zero status
make[5]: "/usr/share/mk/bsd.compiler.mk" line 37: Unable to determine compiler type for clang33.  Consider setting COMPILER_TYPE.
===> devel/ccons failed
*** [describe.devel] Error code 1

make[2]: stopped in /usr/ports
1 error

make[2]: stopped in /usr/ports

********************************************************************
Before reporting this error, verify that you are running a supported
version of FreeBSD (see http://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not supported with partial or out-of-date ports collections.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_at_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[1]: stopped in /usr/ports
*** Error code 1

Stop.
make: stopped in /usr/ports


If I go to the offending port:

# cd /usr/ports/devel/ccons/
# make describe
clang33: not found
make: "/usr/share/mk/bsd.compiler.mk" line 24: warning: "clang33 --version" returned non-zero status
make: "/usr/share/mk/bsd.compiler.mk" line 37: Unable to determine compiler type for clang33.  Consider setting COMPILER_TYPE.


I don't have any problems building the INDEX file on 9.3-PRERELEASE
r265940.