patch 7.4.2209
Problem:    Cannot map <M-">. (Stephen Riehm)
Solution:   Solve the memory access problem in another way. (Dominique Pelle)
            Allow for using <M-\"> in a string.
diff --git a/src/syntax.c b/src/syntax.c
index 0face62..19f9bc4 100644
--- a/src/syntax.c
+++ b/src/syntax.c
@@ -7939,7 +7939,7 @@
 		 */
 		for (p = arg, off = 0; off < 100 - 6 && *p; )
 		{
-		    len = trans_special(&p, buf + off, FALSE);
+		    len = trans_special(&p, buf + off, FALSE, FALSE);
 		    if (len > 0)	    /* recognized special char */
 			off += len;
 		    else		    /* copy as normal char */