groff build failure

[Randy Bush]

very current amd64

===> gnu/usr.bin/groff/src/preproc/eqn (all)
c++ -O2 -pipe -I/usr/src/gnu/usr.bin/groff/src/preproc/eqn/../../../../../../contrib/groff/src/preproc/eqn -I. -DHAVE_CONFIG_H -I/usr/src/gnu/usr.bin/groff/src/preproc/eqn/../../../../../../contrib/groff/src/include -I/usr/src/gnu/usr.bin/groff/src/preproc/eqn/../../../src/include -fstack-protector -fno-rtti -fno-exceptions -c eqn.cpp
y.tab.c: In function 'int yygrowstack()':
y.tab.c:703: error: invalid conversion from 'void*' to 'short int*'
y.tab.c:709: error: invalid conversion from 'void*' to 'YYSTYPE*'
*** Error code 1