pg_sendmail function compile problem

I am trying to compile the pg_sendmail function from
ftp://ftp.trurl.anything3d.com/pub/Linux/our/pgsendmail-1.0.tar.gz and I get
the following error message.
I am using 7.1beta3-2 from rpm install.

Here is the error...

# make
/bin/sh ./libtool --mode=compile
gcc -DHAVE_CONFIG_H -I. -I. -I.     -g -O2 -I/usr/local/pgsql/include -I/usr
/include/pgsql -c mail.c
rm -f .libs/mail.lo
gcc -DHAVE_CONFIG_H -I. -I. -I. -g -O2 -I/usr/local/pgsql/include -I/usr/inc
lude/pgsql -c  -fPIC -DPIC mail.c -o .libs/mail.lo
In file included from mail.c:29:
/usr/include/pgsql/utils/elog.h:37: parse error before `CritSectionCount'
/usr/include/pgsql/utils/elog.h:37: warning: data definition has no type or
storage class
make: *** [mail.lo] Error 1

Do I need some other elog.h file?

Thanks for any suggestions. Keep up the good work.
I like postgresql and am always amazed at the steady stream of email! And am
looking forward to the 7.x series :-)
Joseph Showalter