Dump bound symbols for use in downstream bindgen blocklist #3326
Description
I have with N C libraries and N -sys crates. Let's say N=2 call them foo, bar, foo-sys, and bar-sys. Bar drepends on foo, and I want likewise for bar-sys to depend on foo-sys.
To do this, I need bar-sys to blocklist everything that ended up in foo-sys, so it doesn't make fresh, competing bindings for it.
I can write that by hand, but it's not very maintainable. Can i instead dump the symbols when building foo-sys and import that into bar-sys's blacklist?
The importing part is just a little bit of build.rs elbow grease. It's the exporting part that I think will require a new in bindgen itself.