WARNING: uuid.h: present but cannot be compiled

I'm building 8.4beta1 on Mac OS X 10.5.6. I have ossp-uuid installed
with its includes in /usr/local/include/ossp-uuid. I'm building
PostgreSQL like so:

export CPPFLAGS="-I/usr/local/include/ossp-uuid"
./configure --with-libedit-preferred --with-bonjour --with-perl PERL=/
user/local/bin/perl \
--with-openssl --with-pam --with-krb5 --with-libxml --with-ldap --with-
ossp-uuid \
--with-libs=/usr/local/lib --with-includes=/usr/local/include --
prefix=/usr/local/pgsql

Configure generates this warning:

checking uuid.h presence... yes
configure: WARNING: uuid.h: present but cannot be compiled
configure: WARNING: uuid.h:     check for missing prerequisite headers?
configure: WARNING: uuid.h: see the Autoconf documentation
configure: WARNING: uuid.h:     section "Present But Cannot Be Compiled"
configure: WARNING: uuid.h: proceeding with the preprocessor's result
configure: WARNING: uuid.h: in the future, the compiler will take
precedence
configure: WARNING:     ## ---------------------------------------- ##
configure: WARNING:     ## Report this to pgsql-bugs@postgresql.org ##
configure: WARNING:     ## ---------------------------------------- ##
checking for uuid.h... yes

I guess it's finding Apple's uuid.h and not OSSP's? Do I need to set
some other environment variable to tell PostgreSQL where to find the
ossp uuid include?

BTW, I moved OSSP's uuid.h because it caused conflicts with other apps
that just need Apple's uuid.h. This is a known issue for OSSP UUID:

   http://cvs.ossp.org/tktview?tn=164

Best,

David