The following projects fail to declare their dependency on gio-unix-2.0 headers, which produces errors like the following:

src/gcal-shell-search-provider-generated.c:15:12: fatal error: gio/gunixfdlist.h: No such file or directory
 #  include <gio/gunixfdlist.h>
            ^~~~~~~~~~~~~~~~~~~
compilation terminated.

dbus-player.c:22:10: fatal error: gio/gdesktopappinfo.h: No such file or directory
#include <gio/gdesktopappinfo.h>

../plugins/housekeeping/gsd-disk-space.c:32:10: fatal error: gio/gunixmounts.h: No such file or directory
 #include <gio/gunixmounts.h>

• pkgs/applications/audio/audio-recorder/default.nix https://bugs.launchpad.net/audio-recorder/+bug/1784622
• pkgs/applications/backup/deja-dup/default.nix
• pkgs/applications/misc/zathura/core/default.nix
• pkgs/desktops/gnome-3/apps/gnome-calendar/default.nix https://gitlab.gnome.org/GNOME/gnome-calendar/issues/259
• pkgs/desktops/gnome-3/apps/gnome-photos/default.nix
• pkgs/desktops/gnome-3/apps/seahorse/default.nix https://gitlab.gnome.org/GNOME/seahorse/issues/8
• pkgs/desktops/gnome-3/core/baobab/default.nix
• pkgs/desktops/gnome-3/core/evince/default.nix https://gitlab.gnome.org/GNOME/evince/issues/950
• pkgs/desktops/gnome-3/core/gnome-calculator/default.nix
• pkgs/desktops/gnome-3/core/gnome-desktop/default.nix https://gitlab.gnome.org/GNOME/gnome-desktop/issues/10
• pkgs/desktops/gnome-3/core/gnome-settings-daemon/default.nix https://gitlab.gnome.org/GNOME/gnome-settings-daemon/issues/16
• pkgs/desktops/gnome-3/core/gnome-software/default.nix https://gitlab.gnome.org/GNOME/gnome-software/issues/320
• pkgs/desktops/gnome-3/core/gnome-system-log/default.nix
• pkgs/desktops/gnome-3/core/gnome-user-share/default.nix https://gitlab.gnome.org/GNOME/gnome-user-share/issues/1
• pkgs/desktops/gnome-3/core/nautilus/default.nix https://gitlab.gnome.org/GNOME/nautilus/issues/287
• pkgs/desktops/gnome-3/core/totem/default.nix https://gitlab.gnome.org/GNOME/totem/issues/246
• pkgs/desktops/mate/mate-applets/default.nix Undeclared dependency on gio-unix-2.0 mate-desktop/mate-applets#335
• pkgs/desktops/mate/mate-panel/default.nix Undeclared dependency on gio-unix-2.0 mate-desktop/mate-panel#852
• pkgs/desktops/xfce/core/xfce4-power-manager.nix https://gitlab.xfce.org/xfce/xfce4-power-manager/-/issues/39
• gnome-recipes https://gitlab.gnome.org/GNOME/recipes/issues/76
• pkgs/applications/editors/gnome-latex/default.nix https://gitlab.gnome.org/GNOME/gnome-latex/issues/63
• gnome-flashback https://gitlab.gnome.org/GNOME/gnome-flashback/issues/3
• gnome-panel https://gitlab.gnome.org/GNOME/gnome-panel/issues/6
• gnome-applets https://gitlab.gnome.org/GNOME/gnome-applets/issues/3

We should report it upstream so they can fix it. Try building the package without the hack to see the error.