buildsys: Move usb redir cflags/libs to per object

Signed-off-by: Fam Zheng <famz@redhat.com>
Message-Id: <20170907082918.7299-10-famz@redhat.com>
Reviewed-by: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: Fam Zheng <famz@redhat.com>
2 files changed