patch 8.0.1722: cannot specify a minimal size for a terminal window

Problem:    Cannot specify a minimal size for a terminal window.
Solution:   Support the "rows*cols" format for 'winsize'.
diff --git a/src/option.c b/src/option.c
index 9ebc511..ea8c6af 100644
--- a/src/option.c
+++ b/src/option.c
@@ -7464,7 +7464,9 @@
 	if (*curwin->w_p_tms != NUL)
 	{
 	    p = skipdigits(curwin->w_p_tms);
-	    if (p == curwin->w_p_tms || *p != 'x' || *skipdigits(p + 1) != NUL)
+	    if (p == curwin->w_p_tms
+		    || (*p != 'x' && *p != '*')
+		    || *skipdigits(p + 1) != NUL)
 		errmsg = e_invarg;
 	}
     }