diff --git a/sudo.h b/sudo.h
index d51708ec9..c755f63d2 100644
--- a/sudo.h
+++ b/sudo.h
@@ -248,6 +248,8 @@ extern uid_t timestamp_uid;
 
 extern void (*set_perms) __P((int));
 #endif
+#ifndef errno
 extern int errno;
+#endif
 
 #endif /* _SUDO_SUDO_H */
diff --git a/sudo_noexec.c b/sudo_noexec.c
index 2a5080f0b..ccfe01c9e 100644
--- a/sudo_noexec.c
+++ b/sudo_noexec.c
@@ -48,7 +48,9 @@ static const char rcsid[] = "$Sudo$";
  * few programs actually do that.
  */
 
+#ifndef errno
 extern int errno;
+#endif
 
 #define DUMMY(fn, args, atypes)	\
 int				\