Dynamically loading the `compat-libc` breaks `fork(2)` on Genode.
Switch `compat-libc` to a special api package that provides a source
file for statically linking the library, analogous to the `blit`
package. This also requires a quirk in Goa but should prevent breaking
`fork()` and removes the runtime and archive dependencies for Rust
packages using `compat-libc`.
Ref genodelabs/goa#61
9f7e47368f