Deprecate ustat syscall interface

As for sysctl, ustat has been deprecated in favor of {f}statfs.  Also
some newer ports which uses generic interface builds a stub version that
returns ENOSYS.

This patch deprecates ustat interface by removing ustat.h related headers,
adding a compatibility symbol, and avoiding new ports to build and provide
the symbol.

Checked on x86_64-linux-gnu and i686-linux-gnu.  Also checked with a
check-abi on all affected ABIs.

	* NEWS: Add ustat.h deprecation entry.
	* bits/ustat.h: Remove file.
	* misc/sys/ustat.h: Likewise.
	* misc/ustat.h: Likewise.
	* sysdeps/unix/sysv/linux/generic/ustat.c: Likewise.
	* misc/Makefile (headers): Remove ustat.h and sys/ustat.h.
	* misc/ustat.c (__ustat): Rename to __old_ustat and export only in
	compatibility mode.
	* sysdeps/unix/sysv/linux/ustat.c (__ustat): Likewise.
	* sysdeps/unix/sysv/linux/mips/ustat.c: Define DEV_TO_KDEV and use
	generic Linux implementation.

4 files changed, 19 insertions, 43 deletions

diff --git a/misc/Makefile b/misc/Makefile
index a5076b3672..a1d568b981 100644
--- a/misc/Makefile
+++ b/misc/Makefile
@@ -31,7 +31,7 @@ headers	:= sys/uio.h bits/uio-ext.h bits/uio_lim.h \
 	   sys/mman.h sys/param.h bits/param.h \
 	   fstab.h mntent.h search.h err.h error.h \
 	   sys/queue.h sysexits.h syscall.h sys/syscall.h sys/swap.h \
-	   sys/select.h ustat.h sys/ustat.h bits/ustat.h sys/sysinfo.h \
+	   sys/select.h sys/sysinfo.h \
 	   regexp.h bits/select.h bits/mman.h sys/xattr.h \
 	   syslog.h sys/syslog.h \
 	   bits/syslog.h bits/syslog-ldbl.h bits/syslog-path.h bits/error.h \
diff --git a/misc/sys/ustat.h b/misc/sys/ustat.h
deleted file mode 100644
index 828ca4199b..0000000000
--- a/misc/sys/ustat.h
+++ /dev/null
@@ -1,37 +0,0 @@
-/* Header describing obsolete `ustat' interface.
-   Copyright (C) 1996-2018 Free Software Foundation, Inc.
-   This file is part of the GNU C Library.
-
-   The GNU C Library is free software; you can redistribute it and/or
-   modify it under the terms of the GNU Lesser General Public
-   License as published by the Free Software Foundation; either
-   version 2.1 of the License, or (at your option) any later version.
-
-   The GNU C Library is distributed in the hope that it will be useful,
-   but WITHOUT ANY WARRANTY; without even the implied warranty of
-   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
-   Lesser General Public License for more details.
-
-   You should have received a copy of the GNU Lesser General Public
-   License along with the GNU C Library; if not, see
-   <http://www.gnu.org/licenses/>.  */
-
-/*
- * This interface is obsolete.  Use <sys/statfs.h> instead.
- */
-
-#ifndef _SYS_USTAT_H
-#define	_SYS_USTAT_H	1
-
-#include <features.h>
-
-#include <sys/types.h>
-#include <bits/ustat.h>
-
-__BEGIN_DECLS
-
-extern int ustat (__dev_t __dev, struct ustat *__ubuf) __THROW;
-
-__END_DECLS
-
-#endif /* sys/ustat.h */
diff --git a/misc/ustat.c b/misc/ustat.c
index e5abedae7b..2c40e2a3cb 100644
--- a/misc/ustat.c
+++ b/misc/ustat.c
@@ -16,14 +16,28 @@
    License along with the GNU C Library; if not, see
    <http://www.gnu.org/licenses/>.  */
 
-#include <unistd.h>
-#include <errno.h>
-#include <sys/ustat.h>
+#include <shlib-compat.h>
+
+/* This deprecated syscall is no longer used (replaced with {f}statfs).  */
+#if SHLIB_COMPAT(libc, GLIBC_2_0, GLIBC_2_28)
+
+# include <unistd.h>
+# include <errno.h>
+
+struct ustat
+ {
+   __daddr_t f_tfree;         /* Number of free blocks.  */
+   __ino_t f_tinode;          /* Number of free inodes.  */
+   char f_fname[6];
+   char f_fpack[6];
+};
 
 int
-ustat (dev_t dev, struct ustat *ust)
+__old_ustat (dev_t dev, struct ustat *ust)
 {
   __set_errno (ENOSYS);
   return -1;
 }
 stub_warning (ustat)
+compat_symbol (libc, __old_ustat, ustat, GLIBC_2_0);
+#endif
diff --git a/misc/ustat.h b/misc/ustat.h
deleted file mode 100644
index cba150e446..0000000000
--- a/misc/ustat.h
+++ /dev/null
@@ -1 +0,0 @@
-#include <sys/ustat.h>