patch 7.4.1976
Problem:    Number variables are not 64 bits while they could be.
Solution:   Add the num64 feature. (Ken Takata)
diff --git a/src/ex_cmds.c b/src/ex_cmds.c
index 088e1ac..e7b3b28 100644
--- a/src/ex_cmds.c
+++ b/src/ex_cmds.c
@@ -289,10 +289,10 @@
     union {
 	struct
 	{
-	    long	start_col_nr;		/* starting column number */
-	    long	end_col_nr;		/* ending column number */
+	    varnumber_T	start_col_nr;		/* starting column number */
+	    varnumber_T	end_col_nr;		/* ending column number */
 	} line;
-	long	value;		/* value if sorting by integer */
+	varnumber_T	value;		/* value if sorting by integer */
 #ifdef FEAT_FLOAT
 	float_T value_flt;	/* value if sorting by float */
 #endif