I wrote:
> ... if you're
> using cc you probably need configure --with-includes=/usr/local/include
> or configure won't think Tcl is installed at all.
I take that back: AFAICT, configure doesn't actually bother to verify
that tcl.h can be found, it just assumes it's out there. If it's not
in your include search path, then the build will fall over later on.
Perhaps we should add a configure test to ensure tcl.h is available if
you've said --with-tcl?
regards, tom lane