patch 8.0.0597: off-by-one error in size computation

Problem:    Off-by-one error in buffer size computation.
Solution:   Use ">=" instead of ">". (Lemonboy, closes #1694)
diff --git a/src/quickfix.c b/src/quickfix.c
index 7b07f93..9626cfa 100644
--- a/src/quickfix.c
+++ b/src/quickfix.c
@@ -919,7 +919,7 @@
 	    }
 	    if (fmt_ptr->flags == '+' && !qi->qf_multiscan)	/* %+ */
 	    {
-		if (linelen > fields->errmsglen)
+		if (linelen >= fields->errmsglen)
 		{
 		    /* linelen + null terminator */
 		    if ((fields->errmsg = vim_realloc(fields->errmsg,
@@ -934,7 +934,7 @@
 		if (regmatch.startp[i] == NULL || regmatch.endp[i] == NULL)
 		    continue;
 		len = (int)(regmatch.endp[i] - regmatch.startp[i]);
-		if (len > fields->errmsglen)
+		if (len >= fields->errmsglen)
 		{
 		    /* len + null terminator */
 		    if ((fields->errmsg = vim_realloc(fields->errmsg, len + 1))
@@ -1017,7 +1017,7 @@
 	fields->namebuf[0] = NUL;	/* no match found, remove file name */
 	fields->lnum = 0;			/* don't jump to this line */
 	fields->valid = FALSE;
-	if (linelen > fields->errmsglen)
+	if (linelen >= fields->errmsglen)
 	{
 	    /* linelen + null terminator */
 	    if ((fields->errmsg = vim_realloc(fields->errmsg,