diff --git a/src/misc2.c b/src/misc2.c
index a20337f..b0673d4 100644
--- a/src/misc2.c
+++ b/src/misc2.c
@@ -2087,29 +2087,37 @@
 
 /*
  * For a growing array that contains a list of strings: concatenate all the
- * strings with a separating comma.
+ * strings with a separating "sep".
  * Returns NULL when out of memory.
  */
     char_u *
-ga_concat_strings(gap)
+ga_concat_strings(gap, sep)
     garray_T *gap;
+    char     *sep;
 {
     int		i;
     int		len = 0;
+    int		sep_len = (int)STRLEN(sep);
     char_u	*s;
+    char_u	*p;
 
     for (i = 0; i < gap->ga_len; ++i)
-	len += (int)STRLEN(((char_u **)(gap->ga_data))[i]) + 1;
+	len += (int)STRLEN(((char_u **)(gap->ga_data))[i]) + sep_len;
 
     s = alloc(len + 1);
     if (s != NULL)
     {
 	*s = NUL;
+	p = s;
 	for (i = 0; i < gap->ga_len; ++i)
 	{
-	    if (*s != NUL)
-		STRCAT(s, ",");
-	    STRCAT(s, ((char_u **)(gap->ga_data))[i]);
+	    if (p != s)
+	    {
+		STRCPY(p, sep);
+		p += sep_len;
+	    }
+	    STRCPY(p, ((char_u **)(gap->ga_data))[i]);
+	    p += STRLEN(p);
 	}
     }
     return s;