/usr/X11R6/include/X11 needed but not found during port builds

[Adam Fabian]

My ports aren't finding the files in /usr/X11R6/include when they are
needed.  (I may be making an overly-sweeping generalization; both
mozilla and firefox apparently failed for this reason)

That's my problem, in a nutshell.  I tend to run make under a clean
environment, since I've found stuff like CDPATH breaks things.  Here's
the sort of environment the port makes run under:

HOME=/home/afabian
PS1='$ '
OPTIND=1
PS2='> '
TERM=dumb
PPID=71625
PATH=/bin:/sbin:/usr/bin:/usr/sbin:/usr/local/bin:/usr/local/sbin
IFS='   
'

Here's /etc/make.conf:

PERL_VER=5.8.5
PERL_VERSION=5.8.5
PERL_ARCH=mach
NOPERL=yo
NO_PERL=yo
NO_PERL_WRAPPER=

I can tweak this to work with a symbolic link, (ln -s
/usr/X11R6/include/X11 /usr/include/X11) but I
can't figure out why it's suddenly broken when it used to work.  

-- 
Adam Fabian (afabian at austin.rr.com)