Trying to install rjags on Mac OS X 10.5

Quoting Prof Brian Ripley <ripley at stats.ox.ac.uk>:

and on my Mac the pkg-config files are in /usr/local/lib/pkgconfig 
and /usr/lib/pkgconfig.  Most likely it would work if PKG_CONFIG_PATH 
is not set, so try that first.

Thanks--but this still doesn't seem to get me anywhere (see below).

Macintosh:Desktop ljs$ which jags
/usr/local/bin/jags
Macintosh:Desktop ljs$ whereis jags
Macintosh:Desktop ljs$


Last login: Sun Dec 30 17:40:41 on ttys001
Macintosh:~ ljs$ echo $PKG_CONFIG_PATH

Macintosh:~ ljs$ cd Desktop/
Macintosh:Desktop ljs$ sudo R CMD INSTALL rjags_1.0.1-1.tar.gz
* Installing to library '/Library/Frameworks/R.framework/Resources/library'
* Installing *source* package 'rjags' ...
checking for pkg-config... /opt/local/bin/pkg-config
checking pkg-config is at least version 0.9.0... yes
checking for JAGS... configure: error: Package requirements (jags = 
1.0.1) were
not met:

No package 'jags' found

Consider adjusting the PKG_CONFIG_PATH environment variable if you
installed software in a non-standard prefix.

ERROR: configuration failed for package 'rjags'
** Removing '/Library/Frameworks/R.framework/Resources/library/rjags'
Macintosh:Desktop ljs$

Would I be right in thinking that the problem is not in fiding the path to
pkg-config but in finding JAGS? I have

Macintosh:Desktop ljs$ which jags
/usr/local/bin/jags


Best wishes,

Lindsay Stirton