patch 8.2.0877: cannot get the search statistics

Problem:    Cannot get the search statistics.
Solution:   Add the searchcount() function. (Fujiwara Takuya, closes #4446)
diff --git a/src/macros.h b/src/macros.h
index 2ac705d..16421d2 100644
--- a/src/macros.h
+++ b/src/macros.h
@@ -33,6 +33,7 @@
 		       : (a)->coladd < (b)->coladd)
 #define EQUAL_POS(a, b) (((a).lnum == (b).lnum) && ((a).col == (b).col) && ((a).coladd == (b).coladd))
 #define CLEAR_POS(a) do {(a)->lnum = 0; (a)->col = 0; (a)->coladd = 0;} while (0)
+#define EMPTY_POS(a) ((a).lnum == 0 && (a).col == 0 && (a).coladd == 0)
 
 #define LTOREQ_POS(a, b) (LT_POS(a, b) || EQUAL_POS(a, b))