Hi, just now I had to debug a doxygen Segmentation Fault. I tried to install doxygen:debug but that wasn't available.
I think it would be nice if these outputs were available by default (but not
installed by default).
If we wanted to do that, we could just adapt guix/build-system/cmake.scm,
guix/build-system/gnu.scm and guix/build-system/glib-or-gtk.scm outputs default
to say '("out" "debug") instead of '("out").
Do we want to do that in one of the larger update cycles?
