A file emacs-20.4/src/ChangeLog includes the following entry:

1997-07-28  Richard Stallman  <rms.ai.mit.edu>
........................
        * cm.h, sysdep.c, terminfo.c [HAVE_LIBNCURSES]:
        Declare ospeed as short, unless NCURSES_OSPEED_T.

Unfortunately nothing in 'configure' for emacss seems to be checkin
for that.  The net effect is that emacs declares 'ospeed' as short
while libraries, which access the same global variable, treat that
as 'speed_t'.  At least with ncurses-4.2-25, as included in RH 6.1
distribution, these two types are not the same.

On Alpha, in particular, this has an effect of generating "unaligned
access" messages from a kernel on every access from libraries to that
variable.  In general it seems that emacs works more by luck
than anything else as some not entirely random memory is clobbered
on every write and a garbage retrieved on reads.

This can be fixed by adding NCURSES_OSPEED_T to compilation flags
in emacs.spec file and recompiling emacs binaries.  A patch to spec
file is included below.

   Michal Jaegermann,
   michal