[mod_python] Snapshot building error

Hi all,

I'm attempting to build the latest snapshots of mod_python from the 
apache CVS (so that I can use sessions), and my build is failing at the 
PSP stage of things.

flex is complaining about its invocation from the Makefile:

/usr/local/bin/flex -R -opsp_parser.c --header-file=include/psp_flex.h 
psp_parser.l
/usr/local/bin/flex: unknown flag 'R'.  For usage, try
         /usr/local/bin/flex --help
*** Error code 1

Stop in /root/httpd-python/dist/src (line 79 of Makefile).
*** Error code 1

Stop in /root/httpd-python/dist (line 65 of Makefile).
*** Error code 1

Stop in /root/httpd-python (line 73 of Makefile).


I'm using flex 2.5.4 (this is the latest version available from 
ftp.gnu.org), building on OpenBSD 3.3-STABLE.

Anyone have any suggestions?

Many thanks,

Paul