cmake: fix doxygen generation
cmake: fix doxygen generation

Former-commit-id: 5b4e3755c233d953c1d10d0af75264026b4e0543
FabienPean/sofa,FabienPean/sofa,Anatoscope/sofa,Anatoscope/sofa,hdeling/sofa,FabienPean/sofa,hdeling/sofa,hdeling/sofa,Anatoscope/sofa,Anatoscope/sofa,FabienPean/sofa,hdeling/sofa,FabienPean/sofa,hdeling/sofa,Anatoscope/sofa,hdeling/sofa,Anatoscope/sofa,FabienPean/sofa,hdeling/sofa,FabienPean/sofa,Anatoscope/sofa,hdeling/sofa,hdeling/sofa,Anatoscope/sofa,FabienPean/sofa,Anatoscope/sofa,hdeling/sofa,FabienPean/sofa,FabienPean/sofa