Clean up ill-advised or unusual header guards

Leading underscores are ill-advised because such identifiers are
reserved.  Trailing underscores are merely ugly.  Strip both.

Our header guards commonly end in _H.  Normalize the exceptions.

Macros should be ALL_CAPS.  Normalize the exception.

Done with scripts/clean-header-guards.pl.

include/hw/xen/interface/ and tools/virtiofsd/ left alone, because
these were imported from Xen and libfuse respectively.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20220506134911.2856099-3-armbru@redhat.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>

include/chardev/char-socket.h

@@ -21,8 +21,9 @@
  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  * THE SOFTWARE.
  */
-#ifndef CHAR_SOCKET_H_
-#define CHAR_SOCKET_H_
+
+#ifndef CHAR_SOCKET_H
+#define CHAR_SOCKET_H
 
 #include "io/channel-socket.h"
 #include "io/channel-tls.h"
@@ -83,4 +84,4 @@ typedef struct SocketChardev SocketChardev;
 DECLARE_INSTANCE_CHECKER(SocketChardev, SOCKET_CHARDEV,
                          TYPE_CHARDEV_SOCKET)
 
-#endif /* CHAR_SOCKET_H_ */
+#endif /* CHAR_SOCKET_H */