XPutBackEvent copies an XEvent internally, so the pointer passed in must
point to an actual XEvent object, not an XConfigureEvent, which is
smaller. This avoids an invalid stack read.

git-svn-id: https://svn.code.sf.net/p/freeglut/code/trunk@1680 7f0cb862-5218-0410-a997-914c9d46530a
Merge branch 'svn/trunk'