bash-4.4$ guix package -i glu
Le paquet suivant sera installé:
   glu	9.0.0	/gnu/store/x0r6q7b3c24yg7kgqab92ngg4q68knn7-glu-9.0.0

guix package: error: profile contains conflicting entries for mesa:out
guix package: error:   first entry: mesa@17.1.4:out /gnu/store/s9nzr0s4n6v0cj3dzafmycxxx2dkmgrj-mesa-17.1.4
guix package: error:    ... propagated from glu@9.0.0
guix package: error:   second entry: mesa@17.0.6:out /gnu/store/p9rv7a71z7klykjg24f0js8ahn2yjpqr-mesa-17.0.6
guix package: error:    ... propagated from gtk+@3.22.15