Fix a few compiler warnings.  Fix crash with encrypted undo file.
diff --git a/src/syntax.c b/src/syntax.c
index c19c5d9..370bc76 100644
--- a/src/syntax.c
+++ b/src/syntax.c
@@ -235,7 +235,7 @@
 
 /*
  * Another Annoying Hack(TM):  To prevent rules from other ":syn include"'d
- * files from from leaking into ALLBUT lists, we assign a unique ID to the
+ * files from leaking into ALLBUT lists, we assign a unique ID to the
  * rules in each ":syn include"'d file.
  */
 static int current_syn_inc_tag = 0;
@@ -4500,11 +4500,13 @@
 	    }
 	    else
 #endif
+	    {
 #ifdef FEAT_CONCEAL
 		*conceal_char = arg[6];
 #else
 		;
 #endif
+	    }
 	    arg = skipwhite(arg + 7);
 	}
 	else