setting ./configure environmentals question

[Tom Poe]

I want to install tarball of gimp-gap, since there's no rpm available to 
work with gimp2.2.  Naturally, it won't find gimp on my FC5, but I don't 
know what to do with message.  Any help appreciated:
[message]
checking for GIMP... configure: error: Package requirements (gimp-2.0 >= 
2.2.0 gimpui-2.0 >= 2.2.0 gimpthumb-2.0) were not met.
Consider adjusting the PKG_CONFIG_PATH environment variable if you
installed software in a non-standard prefix.

Alternatively you may set the GIMP_CFLAGS and GIMP_LIBS environment 
variables
to avoid the need to call pkg-config.  See the pkg-config man page for
more details.
[tom at localhost gimp-gap-2.2.0]$ echo $PKG_CONFIG_PATH