swig won't build

install-swig.sh ends with an error:

    make[1]: Entering directory '/home/eekee/forth/gforth-git/swig/Source'
    /bin/bash ../Tools/config/ylwrap CParse/parser.y y.tab.c CParse/parser.c y.tab.h `echo CParse/parser.c | sed -e s/cc$/hh/ -e s/cpp$/hpp/ -e s/cxx$/hxx/ -e s/c++$/h++/ -e s/c$/h/` y.output CParse/parser.output -- yacc -d 
     
     fatal error:invalid escape, or illegal reserved word: expect, /home/eekee/forth/gforth-git/swig/Source/CParse/parser.y:23
    make[1]: *** [Makefile:1042: CParse/parser.c] Error 1
    make[1]: Leaving directory '/home/eekee/forth/gforth-git/swig/Source'
    make: *** [Makefile:37: source] Error 2

i haven't a clue what to make of that, never having used yacc or bison before.

can i use gforth's c interface without swig? is it needed for structs?