[R-SIG-Mac] Unable to find pkg-config during install

[David Winsemius]

I am getting a error message during an effort to use the Package  
Installer with a source copy of cairoDevice:

* Installing *source* package 'cairoDevice' ...
checking for pkg-config... no
ERROR: Cannot find pkg-config.
ERROR: configuration failed for package 'cairoDevice'
--------
I seem to have pkg-config per locate from the Terminal:

david-winsemiuss-mac-pro:~ davidwinsemius$ locate pkg-config
/Library/Frameworks/GTK+.framework/Versions/2.14.X11/Resources/bin/pkg- 
config
/sw/bin/pkg-config
/sw/share/man/man1/pkg-config.1
/usr/X11/share/man/man1/pkg-config.1.gz
/usr/share/zsh/4.3.4/functions/_pkg-config
------
The UNIX Appendix of the Installation Manual (p 29) says: "Mac OS X  
comes with none of these libraries, but cairo support has been added  
to the binary distribution: pkg-config is still needed and can be  
compiled from the sources. "

But that is not particularly helpful to me. Is there some environment  
variable or path has not been defined properly? I tried downloading  
pkgconfig-0.18 but its README file is not sufficiently detailed for my  
level of understanding of the UNIX underbelly of Mac OS X.

 > sessionInfo()
R version 2.8.1 Patched (2009-01-19 r47650)
i386-apple-darwin9.6.0

locale:
en_US.UTF-8/en_US.UTF-8/C/C/en_US.UTF-8/en_US.UTF-8

attached base packages:
[1] splines   stats     graphics  grDevices utils     datasets   
methods   base

other attached packages:
[1] Design_2.2-0    survival_2.35-4 Hmisc_3.6-0

loaded via a namespace (and not attached):
[1] cluster_1.12.0  grid_2.8.1      lattice_0.17-25 tools_2.8.1
Warning message:
In install.packages(c("cairoDevice"), lib = "/Library/Frameworks/ 
R.framework/Resources/library/",  :
   installation of package 'cairoDevice' had non-zero exit status
 >

David Winsemius, MD
Heritage Laboratories
West Hartford, CT