diff --git a/sys/src/ape/lib/9/libc.h b/sys/src/ape/lib/9/libc.h
index d19232eb6..d5457f83e 100644
--- a/sys/src/ape/lib/9/libc.h
+++ b/sys/src/ape/lib/9/libc.h
@@ -180,6 +180,9 @@ extern	int	enc32chr(int);
 extern	int	dec16chr(int);
 extern	int	enc16chr(int);
 
+extern	int	idn2utf(char *, char *, int);
+extern	int	utf2idn(char *, char *, int);
+
 extern int tokenize(char*, char**, int);
 extern int getfields(char*, char**, int, int, char*);
 extern int gettokens(char*, char**, int, char*);
diff --git a/sys/src/ape/lib/9/mkfile b/sys/src/ape/lib/9/mkfile
index b7398e2e8..d5bee17d9 100644
--- a/sys/src/ape/lib/9/mkfile
+++ b/sys/src/ape/lib/9/mkfile
@@ -12,6 +12,7 @@ OFILES=\
 	getcallerpc.$O\
 	getfcr.$O\
 	getfields.$O\
+	idn.$O\
 	mount.$O\
 	rendezvous.$O\
 	rfork.$O\
@@ -66,3 +67,6 @@ u32.$O: ../../../libc/port/u32.c
 
 u64.$O: ../../../libc/port/u64.c
 	$CC $CFLAGS -I. ../../../libc/port/u64.c
+
+idn.$O: ../../../libc/9sys/idn.c
+	$CC $CFLAGS -I. ../../../libc/9sys/idn.c