patch 8.2.1909: number of status line items is limited to 80

Problem:    Number of status line items is limited to 80.
Solution:   Dynamically allocate the arrays. (Rom Grk, closes #7181)

src/structs.h

@@ -1229,14 +1229,15 @@ struct mapblock
 #endif
 };
 
+
 /*
  * Used for highlighting in the status line.
  */
-struct stl_hlrec
+typedef struct
 {
     char_u	*start;
     int		userhl;		// 0: no HL, 1-9: User HL, < 0 for syn ID
-};
+} stl_hlrec_T;
 
 
 /*