syscall: remove Ustat

glibc 2.28 removes ustat.h and the ustat function entirely, which
breaks syscall.Ustat.

Updates golang/go#25990

Change-Id: I430802c86389a02cb4a0cd6caff36fa542d98f2f
Reviewed-on: https://go-review.googlesource.com/120535
Reviewed-by: Than McIntosh <thanm@google.com>
diff --git a/libgo/config.h.in b/libgo/config.h.in
index 57560cd..de57d0c 100644
--- a/libgo/config.h.in
+++ b/libgo/config.h.in
@@ -343,9 +343,6 @@
 /* Define to 1 if you have the `unshare' function. */
 #undef HAVE_UNSHARE
 
-/* Define to 1 if you have the <ustat.h> header file and it works. */
-#undef HAVE_USTAT_H
-
 /* Define to 1 if you have the `utimensat' function. */
 #undef HAVE_UTIMENSAT
 
diff --git a/libgo/configure b/libgo/configure
index 66942ed..7166f94 100755
--- a/libgo/configure
+++ b/libgo/configure
@@ -14760,39 +14760,6 @@
 done
 
 
-{ $as_echo "$as_me:${as_lineno-$LINENO}: checking whether <ustat.h> can be used" >&5
-$as_echo_n "checking whether <ustat.h> can be used... " >&6; }
-if test "${libgo_cv_c_ustat_h+set}" = set; then :
-  $as_echo_n "(cached) " >&6
-else
-  CFLAGS_hold=$CFLAGS
-CFLAGS="$CFLAGS -D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE $OSCFLAGS"
-cat confdefs.h - <<_ACEOF >conftest.$ac_ext
-/* end confdefs.h.  */
-
-#include <sys/types.h>
-#ifdef HAVE_LINUX_FILTER_H
-#include <linux/filter.h>
-#endif
-#include <ustat.h>
-
-_ACEOF
-if ac_fn_c_try_compile "$LINENO"; then :
-  libgo_cv_c_ustat_h=yes
-else
-  libgo_cv_c_ustat_h=no
-fi
-rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
-CFLAGS=$CFLAGS_hold
-fi
-{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $libgo_cv_c_ustat_h" >&5
-$as_echo "$libgo_cv_c_ustat_h" >&6; }
-if test $libgo_cv_c_ustat_h = yes; then
-
-$as_echo "#define HAVE_USTAT_H 1" >>confdefs.h
-
-fi
-
  if test "$ac_cv_header_sys_mman_h" = yes; then
   HAVE_SYS_MMAN_H_TRUE=
   HAVE_SYS_MMAN_H_FALSE='#'
diff --git a/libgo/configure.ac b/libgo/configure.ac
index 3cee2c0..1c19275 100644
--- a/libgo/configure.ac
+++ b/libgo/configure.ac
@@ -537,24 +537,6 @@
 #endif
 ])
 
-AC_CACHE_CHECK([whether <ustat.h> can be used],
-[libgo_cv_c_ustat_h],
-[CFLAGS_hold=$CFLAGS
-CFLAGS="$CFLAGS -D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE $OSCFLAGS"
-AC_COMPILE_IFELSE(
-[AC_LANG_SOURCE([
-#include <sys/types.h>
-#ifdef HAVE_LINUX_FILTER_H
-#include <linux/filter.h>
-#endif
-#include <ustat.h>
-])], [libgo_cv_c_ustat_h=yes], [libgo_cv_c_ustat_h=no])
-CFLAGS=$CFLAGS_hold])
-if test $libgo_cv_c_ustat_h = yes; then
-  AC_DEFINE(HAVE_USTAT_H, 1,
-    [Define to 1 if you have the <ustat.h> header file and it works.])
-fi
-
 AM_CONDITIONAL(HAVE_SYS_MMAN_H, test "$ac_cv_header_sys_mman_h" = yes)
 
 AC_CHECK_FUNCS(strerror_r strsignal wait4 mincore setenv unsetenv dl_iterate_phdr)
diff --git a/libgo/go/syscall/libcall_linux_ustat.go b/libgo/go/syscall/libcall_linux_ustat.go
deleted file mode 100644
index f515fce..0000000
--- a/libgo/go/syscall/libcall_linux_ustat.go
+++ /dev/null
@@ -1,12 +0,0 @@
-// Copyright 2015 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-// GNU/Linux library ustat call.
-// This is not supported on some kernels, such as arm64.
-// +build !arm64,!nios2,!riscv64
-
-package syscall
-
-//sys	Ustat(dev int, ubuf *Ustat_t) (err error)
-//ustat(dev _dev_t, ubuf *Ustat_t) _C_int
diff --git a/libgo/mksysinfo.sh b/libgo/mksysinfo.sh
index 92ecb47..48bc71d 100755
--- a/libgo/mksysinfo.sh
+++ b/libgo/mksysinfo.sh
@@ -1164,20 +1164,6 @@
       -e 's/mem_unit/Unit/' \
     >> ${OUT}
 
-# The ustat struct.
-grep '^type _ustat ' gen-sysinfo.go | \
-    sed -e 's/_ustat/Ustat_t/' \
-      -e 's/f_tfree/Tfree/' \
-      -e 's/f_tinode/Tinoe/' \
-      -e 's/f_fname/Fname/' \
-      -e 's/f_fpack/Fpack/' \
-    >> ${OUT}
-# Force it to be defined, as on some older GNU/Linux systems the
-# header file fails when using with <linux/filter.h>.
-if ! grep 'type _ustat ' gen-sysinfo.go >/dev/null 2>&1; then
-  echo 'type Ustat_t struct { Tfree int32; Tinoe uint64; Fname [5+1]int8; Fpack [5+1]int8; }' >> ${OUT}
-fi
-
 # The utimbuf struct.
 grep '^type _utimbuf ' gen-sysinfo.go | \
     sed -e 's/_utimbuf/Utimbuf/' \
diff --git a/libgo/sysinfo.c b/libgo/sysinfo.c
index fb11826..4ab798c 100644
--- a/libgo/sysinfo.c
+++ b/libgo/sysinfo.c
@@ -144,9 +144,6 @@
 #if defined(HAVE_SYS_SYSINFO_H)
 #include <sys/sysinfo.h>
 #endif
-#if defined(HAVE_USTAT_H)
-#include <ustat.h>
-#endif
 #if defined(HAVE_UTIME_H)
 #include <utime.h>
 #endif