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
Implement FBSD_1.0 versions of libc functions ('stat', 'fstat'). The
functions are versioned with @FBSD_1.0, and therefore, will not clash
with libc during linking. However, to be called by our dynamic linker,
the library must be before libc in the NEEDED section of the binary
using it. This requires the lib to be in front of libc in the LIBS
variable. The library currently will call libc 'stat' and 'fstat' by
looking up the symbols via 'dlsym'.
Ref genodelabs/goa#61
