build-sys: cleanup library symbol files

Signed-off-by: Karel Zak <kzak@redhat.com>
agetty: don't ignore TERM

Fix command line parsing to not ignore term setting if no baud
specified, for example:

  /sbin/agetty ttyS0 vt100

Signed-off-by: Karel Zak <kzak@redhat.com>