sysconf: Fix missing definition of UIO_MAXIOV on Linux [BZ #22321]

After commit 37f802f86400684c8d13403958b2c598721d6360 (Remove
__need_IOV_MAX and __need_FOPEN_MAX), UIO_MAXIOV is no longer supplied
(indirectly) through <bits/stdio_lim.h>, so sysdeps/posix/sysconf.c no
longer sees the definition.

1 files changed, 27 insertions, 0 deletions

diff --git a/sysdeps/unix/sysv/linux/tst-sysconf-iov_max-uapi.c b/sysdeps/unix/sysv/linux/tst-sysconf-iov_max-uapi.c
new file mode 100644
index 0000000000..1240b846e6
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/tst-sysconf-iov_max-uapi.c
@@ -0,0 +1,27 @@
+/* Check IOV_MAX definition: Helper function to capture UAPI header value.
+   Copyright (C) 2017 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/>.  */
+
+/* Use a separate function to avoid header compatibility issues.  */
+
+#include <linux/uio.h>
+
+long
+uio_maxiov_value (void)
+{
+  return UIO_MAXIOV;
+}