Description of problem:

Installing 2:2.2.11-0.fc5.1 from updates-testing gives the following errors:

Package gtk+-2.0 was not found in the pkg-config search path.
Perhaps you should add the directory containing `gtk+-2.0.pc'
to the PKG_CONFIG_PATH environment variable
No package 'gtk+-2.0' found
Package glib-2.0 was not found in the pkg-config search path.
Perhaps you should add the directory containing `glib-2.0.pc'
to the PKG_CONFIG_PATH environment variable
No package 'glib-2.0' found

repeated 4 times each.  Error is coming from /usr/sbin/xsane-install-gimp-plugin
which calls /usr/bin/gimptool-2.0 --gimpplugindir, which does:

++ pkg-config --cflags gtk+-2.0
Package gtk+-2.0 was not found in the pkg-config search path.
Perhaps you should add the directory containing `gtk+-2.0.pc'
to the PKG_CONFIG_PATH environment variable
No package 'gtk+-2.0' found


Looks like some missing Requires(pre/post), or better yet fix gimptool-2.0 to
not call pkg-config unless it needs to (it doesn't for --gimpplugindir and
--version).