In gtkmm-devel-1.2.1-1 (RawHide Powertools), the gtk-- include files seem to have landed in /usr/include instead of /usr/include/gtk--, possibly due to the new %configure macro. This must be wrong. As a side effect, this package (namely one header file) clashes with ncurses-devel.
I know. I am planning on rebuilding this with the correct location once it actually rebuilds with the version of gcc we are using. Thanks for noticing though :)
OK. It's being built right now. You should see it it rawhide the next time it's updated. Tim