libports: add libc's rpc framework headers

Certain rpc headers are needed for compiling getaddrinfo.c. Unfortunatly
that means we have to generate _a few_ header files which we do when we
prepare the libc.

These header files need to be created before the symlinks. Also, some of
these header files depend on a patch. Therefore we apply the patches
first, generate the header files and in the end we create the symlinks.
Noux: add noux-pkg/etc

This package provides files in /etc which are needed for domain
resolving etc. pp.
Noux: add noux-pkg/lynx

Explanation why --disable-rpath-hack is needed:

When building on pistachio_x86 $(LDFLAGS) contains '-L[...]/l4/lib'
which will be transformed by autoconf to '-rpath [...]/l4/lib'.
Now the problem at hand is that we pretend to be FreeBSD when we are
actually not. So autoconf assumes it is valid to use '-path'  when it
is actually not.

Also we use zlib for (de)compressing gzipped streams/files instead of
calling gzip as this currently somewhat buggy.
Noux: rename noux-pkg/gnu-netcat

The other GNU based packages do not have a gnu- prefix either.
Noux: use counter for gettimeofday()

There are certain issues which currently prevent us from writing proper
implementations for time related functions. For now we provide a simple
counter instead to make programms like ping(1) happy.
Noux: add F_GETFL handling to terminal_io_channel

There are certain programms which check if an fd is open by calling
fcntl(fd, F_GETFL, ...). So to keep them happy we return true if
such an request was done to our terminal fd's.
Noux: add FIONBIO handling support to libc_noux
Noux: add F_SETFL to libc_noux's fcntl()

Among other things it is used to set non-blocking mode, so we should
support it (e.g. fcntl(d, F_SETFL, fl | O_NONBLOCK)).
Noux/net: add F_SETFL sup. to socket_io_channel

netcat uses F_SETFL with O_NONBLOCK to set the socket to non-blocking
mode.
Noux/net: add explicit clear_unblock() call...

... and disable a few debug messages.
Noux/net: several changes to Socket_io_channel

These changes include the handling of the FIONBIO ioctl() request
an also fixes a bug regarding the io_check_unblock() method.

check_unblock() did not use the arguments at all, which results in
wrong behaviour in certain situatutions.

Socket_io_channel's write() method did not implement the right
interface and was next to useless. Luckily, you normally do not use
write(1) on a socket.
Noux: add cleanup_socket_descriptor()

This function removes all currently used socket descriptors from the
socket descriptor registry. It is only called when a child is exiting.
Noux/net: add reset_all() method to sd registry

This method is called when a child is exiting to remove all remaining
sockets from the socket descriptor registry to close all sockets.
Noux: add timeout handling to select()

Previously there was not actual timeout handling. If a select() call
set an timeout it would be set to zero instead and was always handled
as blocking i/o. While this works fine for file descriptors which will
be triggerd externally (for example vim through terminal i/o) it does
not work at all for socket descriptors and network operations in
general.

So this commit introduces proper timeout handling and changes the
behaviour of SYSCALL_SELECT so that it now returns more than just one
descriptor at a time.

noux/minimal and noux/net now depend on thread and alarm libraries.
Noux: add is_nonblocking() method

Certain programs tend to set their sockets non-blocking.
As previously descriptors in Noux were only blocking we now introduce
a method to mark the used Io_channel as non-blocking.
Noux: remove {get,free}addrinfo implementation

Remove all unused code because we now use the libc's implementation
only.
libports: add libc-rpc
libports: add needed files to libc-net
libports: add poll() to libc

Implements poll() via select() for certain programs like OpenSSH
which need it.

(This implementation is actually based OpenSSHp's compat function.)
libports: remove passwd functions from libc

Removes getpwent.c from build because the passwd facilities provided by
the FreeBSD libc will not be used anyway and add stub functions instead.
Now services which need these functions have to implement their own
(e.g. libc_noux).