flex-2.5.31 on MacOS X.3.8

[Hans Aberg]

I got the error below, when doing a "make" on flex-2.5.31 under Mac 
OS X.3.8. It uses:
    gcc (GCC) 3.3 20030304 (Apple Computer, Inc. build 1495)

filter.c: In function `filter_apply_chain':
filter.c:161: error: invalid lvalue in assignment
filter.c:163: error: invalid lvalue in assignment
filter.c:184: error: invalid lvalue in assignment
make[2]: *** [filter.o] Error 1
make[1]: *** [all-recursive] Error 1
make: *** [all] Error 2

--
  Hans Aberg