Integer overflow fixes for scrolling, etc.

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+ 2011-09-04  Paul Eggert  <eggert@cs.ucla.edu>
+ 
++      Integer overflow fixes for scrolling, etc.
++      Without this fix, Emacs silently mishandles large integers sometimes.
++      For example, "C-u 4294967297 M-x recenter" was be treated as if
++      it were "C-u 1 M-x recenter" on a typical 64-bit host.
++
+       * xdisp.c: Integer overflow fix.
+       (try_window_id): Check Emacs fixnum range before converting to 'int'.
+ 
+       * window.c: Integer overflow fixes.
+       (window_scroll_line_based, Frecenter):
+       Check that an Emacs fixnum is in range before assigning it to 'int'.
+       (Frecenter, Fmove_to_window_line): Use EMACS_INT, not int, for
+       values converted from Emacs fixnums.
+       (Frecenter): Don't wrap around a line count if it is out of 'int'
+       range; instead, treat it as an extreme value.
+       (Fset_window_configuration, compare_window_configurations):
+       Use ptrdiff_t, not int, for index that might exceed 2 GiB.
+ 
+       * search.c: Integer overflow fixes
+       (Freplace_match): Use ptrdiff_t, not int, for indexes that can
+       exceed INT_MAX.  Check that EMACS_INT value is in range before
+       assigning it to the (possibly-narrower) index.
+       (match_limit): Don't assume that a fixnum can fit in 'int'.
+ 
+       * print.c: Integer overflow fix.
+       (print_object): Use ptrdiff_t, not int, for index that can
+       exceed INT_MAX.
+ 
+       * indent.c: Integer overflow fixes.
+       (position_indentation): Now takes ptrdiff_t, not int.
+       (Fvertical_motion): Don't wrap around LINES values that don't fit
+       in 'int'.  Instead, treat them as extreme values.  This is good
+       enough for windows, which can't have more than INT_MAX lines anyway.
+ 
  2011-09-03  Lars Magne Ingebrigtsen  <larsi@gnus.org>
  
        * Require libxml/parser.h to avoid compilation warning.