www/firefox: configure: error: --enable-chrome-format must be set to either jar, flat, or omni

[O. Hartmann]

I'm unable to perform a port update on www/firefox due to the error
shown below.

Ports: Revision: 401759

System: CURRENT: FreeBSD 11.0-CURRENT #35 r290927: Mon Nov 16 12:39:46
CET 2015 amd64

[...]
configure:27490: c++ -o conftest -O2 -pipe -O3 -march=native -O3
-DLIBICONV_PLUG -fstack-protector -fno-strict-aliasing  -DLIBICONV_PLUG
-fno-exceptions -fno-strict-aliasing -fno-rtti -ffunction-sections
-fdata-sections -fno-exceptions -fno-math-errno -std=gnu++0x
-Qunused-arguments -isystem/usr/local/include -DLIBICONV_PLUG
-pthread  -L/usr/local/lib -Wl,-rpath,/usr/local/lib/firefox
-fstack-protector -Wl,-z,noexecstack -Wl,-z,text conftest.C  1>&5
configure: error: --enable-chrome-format must be set to either jar,
flat, or omni *** Fix above errors and then restart with\ "gmake -f
client.mk
build" /usr/ports/www/firefox/work/mozilla-release/client.mk:364:
recipe for target 'configure' failed gmake[2]: *** [configure] Error 1
gmake[2]: Leaving directory '/usr/ports/www/firefox' ===>  Script
"configure" failed unexpectedly. Please report the problem to
gecko at FreeBSD.org [maintainer] and attach the
"/usr/ports/www/firefox/work/mozilla-release/config.log" including the
output of the failure of your make command. Also, it might be a good
idea to provide an overview of all packages installed on your system
(e.g. a /usr/local/sbin/pkg-static info -g -Ea). *** Error code 1

Stop.
make[1]: stopped in /usr/ports/www/firefox
*** Error code 1

Stop.
make: stopped in /usr/ports/www/firefox

===>>> make build failed for www/firefox
===>>> Aborting update

===>>> Update for firefox-41.0.2,1 failed
===>>> Aborting update