ntdll: Use struct mtget.mt_blksiz on systems featuring this.
Work around using struct mtget.mt_gstat on systems lacking this.
diff --git a/configure b/configure
index 2d3080b..fb51ce2 100755
--- a/configure
+++ b/configure
@@ -18074,6 +18074,234 @@
 fi
 
 
+echo "$as_me:$LINENO: checking for struct mtget.mt_blksiz" >&5
+echo $ECHO_N "checking for struct mtget.mt_blksiz... $ECHO_C" >&6
+if test "${ac_cv_member_struct_mtget_mt_blksiz+set}" = set; then
+  echo $ECHO_N "(cached) $ECHO_C" >&6
+else
+  cat >conftest.$ac_ext <<_ACEOF
+/* confdefs.h.  */
+_ACEOF
+cat confdefs.h >>conftest.$ac_ext
+cat >>conftest.$ac_ext <<_ACEOF
+/* end confdefs.h.  */
+#ifdef HAVE_SYS_MTIO_H
+#include <sys/mtio.h>
+#endif
+
+int
+main ()
+{
+static struct mtget ac_aggr;
+if (ac_aggr.mt_blksiz)
+return 0;
+  ;
+  return 0;
+}
+_ACEOF
+rm -f conftest.$ac_objext
+if { (eval echo "$as_me:$LINENO: \"$ac_compile\"") >&5
+  (eval $ac_compile) 2>conftest.er1
+  ac_status=$?
+  grep -v '^ *+' conftest.er1 >conftest.err
+  rm -f conftest.er1
+  cat conftest.err >&5
+  echo "$as_me:$LINENO: \$? = $ac_status" >&5
+  (exit $ac_status); } &&
+	 { ac_try='test -z "$ac_c_werror_flag"			 || test ! -s conftest.err'
+  { (eval echo "$as_me:$LINENO: \"$ac_try\"") >&5
+  (eval $ac_try) 2>&5
+  ac_status=$?
+  echo "$as_me:$LINENO: \$? = $ac_status" >&5
+  (exit $ac_status); }; } &&
+	 { ac_try='test -s conftest.$ac_objext'
+  { (eval echo "$as_me:$LINENO: \"$ac_try\"") >&5
+  (eval $ac_try) 2>&5
+  ac_status=$?
+  echo "$as_me:$LINENO: \$? = $ac_status" >&5
+  (exit $ac_status); }; }; then
+  ac_cv_member_struct_mtget_mt_blksiz=yes
+else
+  echo "$as_me: failed program was:" >&5
+sed 's/^/| /' conftest.$ac_ext >&5
+
+cat >conftest.$ac_ext <<_ACEOF
+/* confdefs.h.  */
+_ACEOF
+cat confdefs.h >>conftest.$ac_ext
+cat >>conftest.$ac_ext <<_ACEOF
+/* end confdefs.h.  */
+#ifdef HAVE_SYS_MTIO_H
+#include <sys/mtio.h>
+#endif
+
+int
+main ()
+{
+static struct mtget ac_aggr;
+if (sizeof ac_aggr.mt_blksiz)
+return 0;
+  ;
+  return 0;
+}
+_ACEOF
+rm -f conftest.$ac_objext
+if { (eval echo "$as_me:$LINENO: \"$ac_compile\"") >&5
+  (eval $ac_compile) 2>conftest.er1
+  ac_status=$?
+  grep -v '^ *+' conftest.er1 >conftest.err
+  rm -f conftest.er1
+  cat conftest.err >&5
+  echo "$as_me:$LINENO: \$? = $ac_status" >&5
+  (exit $ac_status); } &&
+	 { ac_try='test -z "$ac_c_werror_flag"			 || test ! -s conftest.err'
+  { (eval echo "$as_me:$LINENO: \"$ac_try\"") >&5
+  (eval $ac_try) 2>&5
+  ac_status=$?
+  echo "$as_me:$LINENO: \$? = $ac_status" >&5
+  (exit $ac_status); }; } &&
+	 { ac_try='test -s conftest.$ac_objext'
+  { (eval echo "$as_me:$LINENO: \"$ac_try\"") >&5
+  (eval $ac_try) 2>&5
+  ac_status=$?
+  echo "$as_me:$LINENO: \$? = $ac_status" >&5
+  (exit $ac_status); }; }; then
+  ac_cv_member_struct_mtget_mt_blksiz=yes
+else
+  echo "$as_me: failed program was:" >&5
+sed 's/^/| /' conftest.$ac_ext >&5
+
+ac_cv_member_struct_mtget_mt_blksiz=no
+fi
+rm -f conftest.err conftest.$ac_objext conftest.$ac_ext
+fi
+rm -f conftest.err conftest.$ac_objext conftest.$ac_ext
+fi
+echo "$as_me:$LINENO: result: $ac_cv_member_struct_mtget_mt_blksiz" >&5
+echo "${ECHO_T}$ac_cv_member_struct_mtget_mt_blksiz" >&6
+if test $ac_cv_member_struct_mtget_mt_blksiz = yes; then
+
+cat >>confdefs.h <<_ACEOF
+#define HAVE_STRUCT_MTGET_MT_BLKSIZ 1
+_ACEOF
+
+
+fi
+echo "$as_me:$LINENO: checking for struct mtget.mt_gstat" >&5
+echo $ECHO_N "checking for struct mtget.mt_gstat... $ECHO_C" >&6
+if test "${ac_cv_member_struct_mtget_mt_gstat+set}" = set; then
+  echo $ECHO_N "(cached) $ECHO_C" >&6
+else
+  cat >conftest.$ac_ext <<_ACEOF
+/* confdefs.h.  */
+_ACEOF
+cat confdefs.h >>conftest.$ac_ext
+cat >>conftest.$ac_ext <<_ACEOF
+/* end confdefs.h.  */
+#ifdef HAVE_SYS_MTIO_H
+#include <sys/mtio.h>
+#endif
+
+int
+main ()
+{
+static struct mtget ac_aggr;
+if (ac_aggr.mt_gstat)
+return 0;
+  ;
+  return 0;
+}
+_ACEOF
+rm -f conftest.$ac_objext
+if { (eval echo "$as_me:$LINENO: \"$ac_compile\"") >&5
+  (eval $ac_compile) 2>conftest.er1
+  ac_status=$?
+  grep -v '^ *+' conftest.er1 >conftest.err
+  rm -f conftest.er1
+  cat conftest.err >&5
+  echo "$as_me:$LINENO: \$? = $ac_status" >&5
+  (exit $ac_status); } &&
+	 { ac_try='test -z "$ac_c_werror_flag"			 || test ! -s conftest.err'
+  { (eval echo "$as_me:$LINENO: \"$ac_try\"") >&5
+  (eval $ac_try) 2>&5
+  ac_status=$?
+  echo "$as_me:$LINENO: \$? = $ac_status" >&5
+  (exit $ac_status); }; } &&
+	 { ac_try='test -s conftest.$ac_objext'
+  { (eval echo "$as_me:$LINENO: \"$ac_try\"") >&5
+  (eval $ac_try) 2>&5
+  ac_status=$?
+  echo "$as_me:$LINENO: \$? = $ac_status" >&5
+  (exit $ac_status); }; }; then
+  ac_cv_member_struct_mtget_mt_gstat=yes
+else
+  echo "$as_me: failed program was:" >&5
+sed 's/^/| /' conftest.$ac_ext >&5
+
+cat >conftest.$ac_ext <<_ACEOF
+/* confdefs.h.  */
+_ACEOF
+cat confdefs.h >>conftest.$ac_ext
+cat >>conftest.$ac_ext <<_ACEOF
+/* end confdefs.h.  */
+#ifdef HAVE_SYS_MTIO_H
+#include <sys/mtio.h>
+#endif
+
+int
+main ()
+{
+static struct mtget ac_aggr;
+if (sizeof ac_aggr.mt_gstat)
+return 0;
+  ;
+  return 0;
+}
+_ACEOF
+rm -f conftest.$ac_objext
+if { (eval echo "$as_me:$LINENO: \"$ac_compile\"") >&5
+  (eval $ac_compile) 2>conftest.er1
+  ac_status=$?
+  grep -v '^ *+' conftest.er1 >conftest.err
+  rm -f conftest.er1
+  cat conftest.err >&5
+  echo "$as_me:$LINENO: \$? = $ac_status" >&5
+  (exit $ac_status); } &&
+	 { ac_try='test -z "$ac_c_werror_flag"			 || test ! -s conftest.err'
+  { (eval echo "$as_me:$LINENO: \"$ac_try\"") >&5
+  (eval $ac_try) 2>&5
+  ac_status=$?
+  echo "$as_me:$LINENO: \$? = $ac_status" >&5
+  (exit $ac_status); }; } &&
+	 { ac_try='test -s conftest.$ac_objext'
+  { (eval echo "$as_me:$LINENO: \"$ac_try\"") >&5
+  (eval $ac_try) 2>&5
+  ac_status=$?
+  echo "$as_me:$LINENO: \$? = $ac_status" >&5
+  (exit $ac_status); }; }; then
+  ac_cv_member_struct_mtget_mt_gstat=yes
+else
+  echo "$as_me: failed program was:" >&5
+sed 's/^/| /' conftest.$ac_ext >&5
+
+ac_cv_member_struct_mtget_mt_gstat=no
+fi
+rm -f conftest.err conftest.$ac_objext conftest.$ac_ext
+fi
+rm -f conftest.err conftest.$ac_objext conftest.$ac_ext
+fi
+echo "$as_me:$LINENO: result: $ac_cv_member_struct_mtget_mt_gstat" >&5
+echo "${ECHO_T}$ac_cv_member_struct_mtget_mt_gstat" >&6
+if test $ac_cv_member_struct_mtget_mt_gstat = yes; then
+
+cat >>confdefs.h <<_ACEOF
+#define HAVE_STRUCT_MTGET_MT_GSTAT 1
+_ACEOF
+
+
+fi
+
+
 echo "$as_me:$LINENO: checking for struct option.name" >&5
 echo $ECHO_N "checking for struct option.name... $ECHO_C" >&6
 if test "${ac_cv_member_struct_option_name+set}" = set; then