Remove getaddrinfo and freeaddrinfo from the Libc::Plugin and get rid of
the extra libc_resolv library. Remove getaddrinfo/freeaddrinfo symbol
hiding patch for FreeBSD sources. Remove libc_resolv from Makefiles and
run scenarios.
Fix#2273
By building the posix library as shared object with an ABI, we
effectively decouple posix-using programs from the library
implementation (which happens to depend on several os-level APIs such as
the VFS).
