msvcrt: Use BOOL type where appropriate.

dlls/msvcrt/time.c

@@ -41,7 +41,7 @@ static const int MonthLengths[2][12] =
     { 31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 }
 };
 
-static inline int IsLeapYear(int Year)
+static inline BOOL IsLeapYear(int Year)
 {
     return Year % 4 == 0 && (Year % 100 != 0 || Year % 400 == 0);
 }