patch 9.0.2138: Overflow logic requires long long

Problem:  Overflow logic requires long long
Solution: Define vimlong_T data type to make life easier
          for porters

closes: #13598

Signed-off-by: Ernie Rael <errael@raelity.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>

src/misc1.c

@@ -2843,7 +2843,7 @@ vim_append_digit_long(long *value, int digit)
 
 // Return something that fits into an int.
     int
-trim_to_int(long long x)
+trim_to_int(vimlong_T x)
 {
     return x > INT_MAX ? INT_MAX : x < INT_MIN ? INT_MIN : x;
 }