--- a/lib/fseterr.c
+++ b/lib/fseterr.c
@@ -32,13 +32,17 @@
 
 #include "stdio-impl.h"
 
+/* This file is not used on systems that have the __fseterr function,
+   namely musl libc.  */
+
 void
 fseterr (FILE *fp)
 {
   /* Most systems provide FILE as a struct and the necessary bitmask in
      <stdio.h>, because they need it for implementing getc() and putc() as
      fast macros.  */
-#if defined _IO_ftrylockfile || __GNU_LIBRARY__ == 1 /* GNU libc, BeOS, Haiku, Linux libc5 */
+#if defined _IO_EOF_SEEN || defined _IO_ftrylockfile || __GNU_LIBRARY__ == 1
+  /* GNU libc, BeOS, Haiku, Linux libc5 */
   fp->_flags |= _IO_ERR_SEEN;
 #elif defined __sferror || defined __DragonFly__ || defined __ANDROID__
   /* FreeBSD, NetBSD, OpenBSD, DragonFly, Mac OS X, Cygwin, Minix 3, Android */