I posted a question about building with support for the new parser
some weeks back but didn't get around to trying the suggestions till
now. I've installed Bison/Flex and added the bin dir to my system path
so scons should be able to work with it. Scons now hangs at this point
in the build:

Creating library file: libampmidid.a
bison -d --report=itemset -p csound_orc -o Engine\csound_orcparse.c
Engine\csound_orc.y
m4: Files\GnuWin32/share/bison: No such file or directory
m4: c:\Program: No such file or directory
m4: Files\GnuWin32/share/bison/m4sugar/m4sugar.m4: No such file or directory

I tried this with command prompt and also with MSYS. Same results each
time. Anyone have any ideas?