diff --git a/sysdeps/unix/sysv/linux/bits/fcntl-linux.h b/sysdeps/unix/sysv/linux/bits/fcntl-linux.h
index 7e5b0aecdcb4..5a4aad0698b8 100644
--- a/sysdeps/unix/sysv/linux/bits/fcntl-linux.h
+++ b/usr/include/arm-linux-gnueabihf/bits/fcntl-linux.h
@@ -127,11 +127,17 @@ 
    This means that they are inherited across fork or clone with CLONE_FILES
    like BSD (flock) locks, and they are only released automatically when the
    last reference to the the file description against which they were acquired
-   is put. */
+   is put.
+
+   Note that Linux does not support legacy (non-LFS) struct flock on 32-bit
+   arches with OFD locks.  On those arches you need define both _GNU_SOURCE
+   and _FILE_OFFSET_BITS=64.  */
 #ifdef __USE_GNU
-# define F_OFD_GETLK	36
-# define F_OFD_SETLK	37
-# define F_OFD_SETLKW	38
+# if __OFF_T_MATCHES_OFF64_T || defined __USE_FILE_OFFSET64
+#  define F_OFD_GETLK	36
+#  define F_OFD_SETLK	37
+#  define F_OFD_SETLKW	38
+# endif
 #endif
 
 #ifdef __USE_LARGEFILE64