> If useful, here is my mk.conf (also tried everything here, including not having one
> at all):
>
> CFLAGS=-O -march=pentium4 -mfpmath=sse -pipe
> WRKOBJDIR=/var/tmp/pkg
> X11_TYPE=xorg

Here's a bunch of quick hacks :)

First of all, I don't use tools, so in etc/mk.conf I have:
MKTOOLS=no
USETOOLS=never

Second, try to build and install flex:
cd /usr/src/usr.bin/lex
make dependall MKSHARE=no
make install MKSHARE=no

If that does not work, first try:
cd /usr/src/share/mk
make install
cd /usr/src
make includes

Let me know where these get you

Kind regards,
Adam


P.S.: As for CFLAGS, I recommend:
COPTS+=-Os -pipe -mcpu=pentium4 -fomit-frame-pointer
CFLAGS+=${COPTS}