I integrated rapier and rapier-f64. Then I added salva, but now it doesn't build and salva only works with rapier, not rapier64(eg. features="rapier")
https://github.com/appsinacup/godot-rapier-2d
appsinacup/godot-rapier-physics#61

One solution could be to add same as for rapier, single or double builds, and then for feature add rapier or rapier-f64.