fix screen width detection for apt/apt-get lists

3163087b moved SigWinch(int) from apt-get.cc to private-output.cc
without moving #include <sys/ioctl.h>, making SigWinch a nop.

Closes: 748430, 747942

apt-private/private-output.cc

@@ -23,6 +23,7 @@
 #include <langinfo.h>
 #include <unistd.h>
 #include <signal.h>
+#include <sys/ioctl.h>
 
 #include <apti18n.h>
 									/*}}}*/

cmdline/apt-get.cc

@@ -76,7 +76,6 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
-#include <sys/ioctl.h>
 #include <sys/stat.h>
 #include <sys/statfs.h>
 #include <sys/statvfs.h>