Hello Guix, GCC 10 changed the default behavior when encountering multiple definitions of a global (often an enum) [0]. This causes error messages like [1]: --8<---------------cut here---------------start------------->8--- ld: a.o:(.bss+0x0): multiple definition of `a'; main.o:(.data+0x0): first defined here --8<---------------cut here---------------end--------------->8--- Gentoo's tracker for this issue [2] also has some more info. I manually searched Cuirass build logs and found 28 packages failing on x86_64 with this error: arcan-sdl@0.5.5.2-1.b4dd1fb aris@2.2 blastem@0.6.2 chocolate-doom@3.0.1 crispy-doom@5.8.0 geeqie@1.5 glabels@3.4.1 gmtp@1.3.11 gpredict@2.2.1 gtksheet@4.3.5 jumpnbump@1.61 lablgtk@2.18.10 libappindicator@12.10.0 libopenshot@0.2.5 libsrtp@2.3.0 linsmith@0.99.31 megaglest@3.13.0 mupen64plus-core@2.5 ocaml4.07-lablgtk@1.18.10 ocl-icd@2.2.12 opencpn@5.0.0 pcsxr@1.9.95 pipewire@0.2.7 transcode@1.1.7 transmission-remote-gtk@1.4.1 uget@2.2.1 uim-gtk@1.8.8 uim-qt@1.8.8 I submitted an issue upstream for transmission-remote-gtk [3], but I haven't taken a look at the others. Any takers? [0] https://gcc.gnu.org/gcc-10/porting_to.html [1] https://wiki.gentoo.org/wiki/Project:Toolchain/Gcc_10_porting_notes/fno_common [2] https://bugs.gentoo.org/705764 [3] https://github.com/transmission-remote-gtk/transmission-remote-gtk/issues/122 -- Sarah