updated for version 7.3.541
Problem:    When joining lines comment leaders need to be removed manually.
Solution:   Add the 'j' flag to 'formatoptions'. (Lech Lorens)
diff --git a/src/ex_docmd.c b/src/ex_docmd.c
index 44b61df..c1640a3 100644
--- a/src/ex_docmd.c
+++ b/src/ex_docmd.c
@@ -8545,7 +8545,7 @@
 	}
 	++eap->line2;
     }
-    (void)do_join(eap->line2 - eap->line1 + 1, !eap->forceit, TRUE);
+    (void)do_join(eap->line2 - eap->line1 + 1, !eap->forceit, TRUE, TRUE);
     beginline(BL_WHITE | BL_FIX);
     ex_may_print(eap);
 }