[EXPAND] Free IFS state after here document expansion

Here's another bug bisecting to f42e443bb ([EXPAND] Fix
ifsfirst/ifslastp leak, 2010-09-08).  It was found with the following
test case, based on the configure script for Tracker:

	dash -x -c '
		<<-_ACEOF
		$@
		_ACEOF
		exec
	' - abcdefgh
	+
	+ exec   �a
	exec: 1: : Permission denied

The missing ifsfree call is in expandarg when it returns to openhere
during here document expansion.

Reported-by: Aurelien Jarno <aurel32@debian.org>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

ChangeLog

diff --git a/ChangeLog b/ChangeLog
index 44e5bdf..5163479 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+2011-03-15  Jonathan Nieder <jrnieder@gmail.com>
+
+	* Free IFS state after here document expansion.
+
 2011-03-15  Harald van Dijk <harald@gigawatt.nl>
 
 	* Let funcnode refer to a function definition, not its first command.

src/expand.c

diff --git a/src/expand.c b/src/expand.c
index f155ea0..ce60fe9 100644
--- a/src/expand.c
+++ b/src/expand.c
@@ -194,7 +194,8 @@
 	p = _STPUTC('\0', expdest);
 	expdest = p - 1;
 	if (arglist == NULL) {
-		return;			/* here document expanded */
+		/* here document expanded */
+		goto out;
 	}
 	p = grabstackstr(p);
 	exparg.lastp = &exparg.list;
@@ -212,12 +213,14 @@
 		*exparg.lastp = sp;
 		exparg.lastp = &sp->next;
 	}
-	ifsfree();
 	*exparg.lastp = NULL;
 	if (exparg.list) {
 		*arglist->lastp = exparg.list;
 		arglist->lastp = exparg.lastp;
 	}
+
+out:
+	ifsfree();
 }