mailinfo: fix an off-by-one error in the boundary stack

We pre-increment the pointer that we will use to store something at,
so the pointer is already beyond the end of the array if it points
at content[MAX_BOUNDARIES].

Signed-off-by: Junio C Hamano <[email protected]>

Author: gitster

builtin/mailinfo.c

@@ -185,7 +185,7 @@ static void handle_content_type(struct strbuf *line)
 
 	if (slurp_attr(line->buf, "boundary=", boundary)) {
 		strbuf_insert(boundary, 0, "--", 2);
-		if (++content_top > &content[MAX_BOUNDARIES]) {
+		if (++content_top >= &content[MAX_BOUNDARIES]) {
 			fprintf(stderr, "Too many boundaries to handle\n");
 			exit(1);
 		}