msvc: Fix a compiler warning due to an incorrect pointer cast

Signed-off-by: Ramsay Jones <ramsay@ramsay1.demon.co.uk>
Acked-by: Sebastian Schuberth <sschuberth@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

compat/regex/regex.c

@@ -2808,7 +2808,7 @@ re_set_registers (bufp, regs, num_regs, starts, ends)
     {
       bufp->regs_allocated = REGS_UNALLOCATED;
       regs->num_regs = 0;
-      regs->start = regs->end = (regoff_t) 0;
+      regs->start = regs->end = (regoff_t *) 0;
     }
 }