diff --git a/liboath/gl/fseeko.c b/liboath/gl/fseeko.c
index 67bb9ec..6adb80e 100644
--- a/liboath/gl/fseeko.c
+++ b/liboath/gl/fseeko.c
@@ -47,7 +47,7 @@ fseeko (FILE *fp, off_t offset, int whence)
 #endif

   /* These tests are based on fpurge.c.  */
-#if defined _IO_ftrylockfile || __GNU_LIBRARY__ == 1 /* GNU libc, BeOS, Haiku, Linux libc5 */
+#if defined _IO_EOF_SEEN || __GNU_LIBRARY__ == 1 /* GNU libc, BeOS, Haiku, Linux libc5 */
   if (fp->_IO_read_end == fp->_IO_read_ptr
       && fp->_IO_write_ptr == fp->_IO_write_base
       && fp->_IO_save_base == NULL)
@@ -123,7 +123,7 @@ fseeko (FILE *fp, off_t offset, int whence)
           return -1;
         }

-#if defined _IO_ftrylockfile || __GNU_LIBRARY__ == 1 /* GNU libc, BeOS, Haiku, Linux libc5 */
+#if defined _IO_EOF_SEEN || __GNU_LIBRARY__ == 1 /* GNU libc, BeOS, Haiku, Linux libc5 */
       fp->_flags &= ~_IO_EOF_SEEN;
       fp->_offset = pos;
 #elif defined __sferror || defined __DragonFly__ || defined __ANDROID__