* macros.c: Integer and buffer overflow fixes.

* macros.c: Integer and buffer overflow fixes.

* keyboard.h (struct keyboard.kbd_macro_bufsize):
* macros.c (Fstart_kbd_macro, store_kbd_macro_char):
Use ptrdiff_t, not int, for sizes.
Don't increment bufsize until after realloc succeeds.
Check for size-calculation overflow.
(Fstart_kbd_macro): Use EMACS_INT, not int, for XINT result.