Linux: Add missing scheduler constants to <sched.h>

And add a test, misc/tst-sched-consts, that checks
consistency with <sched.h>.

Reviewed-by: Carlos O'Donell <carlos@redhat.com>

sysdeps/unix/sysv/linux/tst-sched-consts.py

@@ -0,0 +1,56 @@
+#!/usr/bin/python3
+# Test that glibc's sched.h constants match the kernel's.
+# Copyright (C) 2018-2024 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
+# <https://www.gnu.org/licenses/>.
+
+import argparse
+import sys
+
+import glibcextract
+import glibcsyscalls
+
+
+def main():
+    """The main entry point."""
+    parser = argparse.ArgumentParser(
+        description="Test that glibc's sched.h constants "
+        "match the kernel's.")
+    parser.add_argument('--cc', metavar='CC',
+                        help='C compiler (including options) to use')
+    args = parser.parse_args()
+    linux_version_headers = glibcsyscalls.linux_kernel_version(args.cc)
+    linux_version_glibc = (6, 10)
+    sys.exit(glibcextract.compare_macro_consts(
+        '#define _GNU_SOURCE 1\n'
+        '#include <sched.h>\n',
+        '#define _GNU_SOURCE 1\n'
+        '#include <linux/sched.h>\n'
+        '#include <linux/sched/types.h>\n',
+        args.cc,
+        'SCHED_.*',
+        # SCHED_ISO is reserved, but not implemented in the kernel.
+        # SCHED_OTHER is the standard name for SCHED_NORMAL.
+        # SCHED_FLAG_ALL will receive more and more flags, so
+        # exposing it to userspace does not seem useful.
+        'SCHED_ISO'
+        '|SCHED_OTHER'
+        '|SCHED_FLAG_ALL',
+        linux_version_glibc > linux_version_headers,
+        linux_version_headers > linux_version_glibc))
+
+if __name__ == '__main__':
+    main()