rcmain: use new $termprog variable

R=rsc
CC=plan9port.codebot
https://codereview.appspot.com/12505045
diff --git a/CONTRIBUTORS b/CONTRIBUTORS
index c49c9cd..b62df5c 100644
--- a/CONTRIBUTORS
+++ b/CONTRIBUTORS
@@ -44,6 +44,7 @@
 Russ Cox <rsc@swtch.com>
 Sean McKean <smckean83@gmail.com>
 Shenghou Ma <minux.ma@gmail.com>
+Steve McCoy <mccoyst@gmail.com>
 Ties Bos <gitbisector@gmail.com>
 Tim Newsham <tim.newsham@gmail.com>
 Tony Lainson <t.lainson@gmail.com>
diff --git a/rcmain b/rcmain
index 448de02..461cb3e 100644
--- a/rcmain
+++ b/rcmain
@@ -23,7 +23,7 @@
 	exit $status
 }
 if(flag i){
-	if(~ $TERM 9term){
+	if(~ $termprog 9term || ~ $termprog win){
 		fn cd {
 			# builtin cd $1 && flag i && awd
 			# is not sufficient when running in a subshell