diff --git a/libgloss/microblaze/linux-inbyte.c b/libgloss/microblaze/linux-inbyte.c
index 58fdf1957..2f8d33871 100644
--- a/libgloss/microblaze/linux-inbyte.c
+++ b/libgloss/microblaze/linux-inbyte.c
@@ -1,3 +1,5 @@
+extern int read (int, char *, int);
+
 int inbyte(void)
 {
 	char ch = 0;
diff --git a/libgloss/microblaze/linux-outbyte.c b/libgloss/microblaze/linux-outbyte.c
index 9d7bc4890..46de511f6 100644
--- a/libgloss/microblaze/linux-outbyte.c
+++ b/libgloss/microblaze/linux-outbyte.c
@@ -1,3 +1,5 @@
+extern int _write (int, char *, int);
+
 void outbyte (unsigned char c)
 {
 	_write(1, &c, 1);