bootstrap: remove 26 more gnulib modules

* send, recv: we use write & read for sockets so don't
need these portability wrappers
* ioctl, fcntl, fcntl-h: any usage of these is conditionally
compiled and excludes Windows
* ttyname_r: this exists in all supported platforms that
we require now
* environ: the tests explicitly declare this global variable
* intprops: the code has been converted / simplified
* nonblocking: we have a custom impl now to work with our
own sockets wrappers
* openpty: custom checks in configure.ac cope with portability
* accept, bind, connect, getpeername, getsockname, listen,
setsockopt, socket: code needing Windows portability uses
our wrapper functions
* close: avoids abort when passed invalid FD on Windows.
Our VIR_FORCE_CLOSE wrapper avoids calling close(-1)
and it is reasonable to abort in other scenarios in
the RPC client
* physmem: the gnulib code has been partially imported
* warnings, manywarnings: copy the files directly into
our local m4 dir
* verify: replaced by G_STATIC_ASSERT
* pthread_sigmask: none of the fixed portability problems
affect libvirt's usage on current supported platforms
* termios: the header is now conditionally included only
when needed
* time_r: replaced with GDateTime APIs

Reviewed-by: Pavel Hrdina <phrdina@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>