It seems we only depend on COMPAT_43 to implement the send() and recv()
routines. We can easily implement them using sendto() and recvfrom(),
just like we do inside our very own C library.
I wasn't able to really test it, apart from simple compilation testing.
I've heard rumours that COMPAT_SVR4 is broken inside execve() anyway.
It's still worth to fix this, because I suspect we'll get rid of
COMPAT_43 somewhere in the future...
Reviewed by: rdivacky
Discussed with: jhb
7969b32c44