commit 57e872301f5e836be2efb8f952f9c9711650b447
  Author: Adam Jackson <ajax@redhat.com>
  Date:   Thu Apr 5 13:07:09 2018 -0400

    mi: Hush an almost certainly bogus warning

    In file included from ../mi/miexpose.c:83:
    ../mi/miexpose.c: In function ‘miHandleExposures’:
    ../include/regionstr.h:174:22: warning: ‘expBox.y2’ may be used uninitialized in this function [-Wmaybe-uninitialized]
         (_pReg)->extents = *(_pBox);
         ~~~~~~~~~~~~~~~~~^~~~~~~~~~
    ../mi/miexpose.c:139:12: note: ‘expBox.y2’ was declared here
         BoxRec expBox;
                ^~~~~~

    etc. It's initialized if (extents), and then only read if (extents),
    but gcc doesn't seem to figure that out. Whatever, bzero it to be
    explicit.
Signed-off-by: Adam Jackson <ajax@redhat.com>
Acked-by: Keith Packard <keithp@keithp.com>