diff --git a/ChangeLog b/ChangeLog
index 9f9630a..2d68917 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,6 +1,10 @@
 2018-08-08  John Ericson  <john.ericson@obsidian.systems>
 
-	* config.sub (abacus, asmjs): Combine some redundant case arms.
+	* config.sub (tile*): Only set 'os' to -linux-gnu if unset.
+
+2018-08-08  John Ericson  <john.ericson@obsidian.systems>
+
+	* config.sub (abacus, asmjs): Combine these redundant case arms.
 
 2018-08-08  John Ericson  <john.ericson@obsidian.systems>
 
diff --git a/config.sub b/config.sub
index 6fc84e8..dddd27d 100755
--- a/config.sub
+++ b/config.sub
@@ -1193,7 +1193,7 @@ case $basic_machine in
 		;;
 	tile*)
 		basic_machine=$basic_machine-unknown
-		os=linux-gnu
+		os=${os:-linux-gnu}
 		;;
 	tx39)
 		basic_machine=mipstx39-unknown