io: add QIOChannelSocket class

Implement a QIOChannel subclass that supports sockets I/O.
The implementation is able to manage a single socket file
descriptor, whether a TCP/UNIX listener, TCP/UNIX connection,
or a UDP datagram. It provides APIs which can listen and
connect either asynchronously or synchronously. Since there
is no asynchronous DNS lookup API available, it uses the
QIOTask helper for spawning a background thread to ensure
non-blocking operation.

Signed-off-by: Daniel P. Berrange <berrange@redhat.com>

scripts/create_config

@@ -61,6 +61,15 @@ case $line in
     value=${line#*=}
     echo "#define $name $value"
     ;;
+ HAVE_*=y) # configuration
+    name=${line%=*}
+    echo "#define $name 1"
+    ;;
+ HAVE_*=*) # configuration
+    name=${line%=*}
+    value=${line#*=}
+    echo "#define $name $value"
+    ;;
  ARCH=*) # configuration
     arch=${line#*=}
     arch_name=`echo $arch | LC_ALL=C tr '[a-z]' '[A-Z]'`