diff --git a/include/stdio.h b/include/stdio.h
--- a/include/stdio.h
+++ b/include/stdio.h
@@ -66,10 +66,12 @@
 #endif
 #endif
 
+#if __LFS_VISIBLE
 #ifndef _OFF64_T_DECLARED
 #define	_OFF64_T_DECLARED
 typedef	__off64_t	off64_t;
 #endif
+#endif
 
 #if __POSIX_VISIBLE >= 200112 || __XSI_VISIBLE
 #ifndef _VA_LIST_DECLARED
@@ -418,7 +420,7 @@
 #if __BSD_VISIBLE
 typedef __ssize_t cookie_read_function_t(void *, char *, size_t);
 typedef __ssize_t cookie_write_function_t(void *, const char *, size_t);
-typedef int cookie_seek_function_t(void *, off64_t *, int);
+typedef int cookie_seek_function_t(void *, __off64_t *, int);
 typedef int cookie_close_function_t(void *);
 typedef struct {
 	cookie_read_function_t	*read;
diff --git a/lib/libc/stdio/fopencookie.c b/lib/libc/stdio/fopencookie.c
--- a/lib/libc/stdio/fopencookie.c
+++ b/lib/libc/stdio/fopencookie.c
@@ -115,7 +115,7 @@
 _fopencookie_seek(void *cookie, fpos_t offset, int whence)
 {
 	struct fopencookie_thunk *thunk;
-	off64_t off64;
+	__off64_t off64;
 	int res;
 
 	switch (whence) {
@@ -140,7 +140,7 @@
 		return (-1);
 	}
 
-	off64 = (off64_t)offset;
+	off64 = (__off64_t)offset;
 	res = thunk->foc_io.seek(thunk->foc_cookie, &off64, whence);
 	if (res < 0)
 		return (res);
diff --git a/sys/sys/types.h b/sys/sys/types.h
--- a/sys/sys/types.h
+++ b/sys/sys/types.h
@@ -175,10 +175,12 @@
 #define	_OFF_T_DECLARED
 #endif
 
+#if __LFS_VISIBLE
 #ifndef _OFF64_T_DECLARED
 typedef	__off64_t	off64_t;	/* file offset (alias) */
 #define	_OFF64_T_DECLARED
 #endif
+#endif
 
 #ifndef _PID_T_DECLARED
 typedef	__pid_t		pid_t;		/* process id */