diff --git a/scripts/sort-makefile-lines.py b/scripts/sort-makefile-lines.py
new file mode 100755
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+++ b/scripts/sort-makefile-lines.py
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+#!/usr/bin/python3
+# Sort Makefile lines as expected by project policy.
+# Copyright (C) 2023 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
+# .
+
+# The project consensus is to split Makefile variable assignment
+# across multiple lines with one value per line. The values are
+# then sorted as described below, and terminated with a special
+# list termination marker. This splitting makes it much easier
+# to add new tests to the list since they become just a single
+# line insertion. It also makes backports and merges easier
+# since the new test may not conflict due to the ordering.
+#
+# Consensus discussion:
+# https://inbox.sourceware.org/libc-alpha/f6406204-84f5-adb1-d00e-979ebeebbbde@redhat.com/
+#
+# To support cleaning up Makefiles we created this program to
+# help sort existing lists converted to the new format.
+#
+# The program takes as input the Makefile to sort correctly,
+# and the output file to write the correctly sorted output
+# (it can be the same file).
+#
+# Sorting is only carried out between two special markers:
+# (a) Marker start is ' += \' (or '= \', or ':= \')
+# (b) Marker end is ' # ' (whitespace matters)
+# With everthing between (a) and (b) being sorted accordingly.
+#
+# You can use it like this:
+# $ scripts/sort-makefile-lines.py < elf/Makefile > elf/Makefile.tmp
+# $ mv elf/Makefile.tmp elf/Makefile
+#
+# The Makefile lines in the project are sorted using the
+# following rules:
+# - All lines are sorted as-if `LC_COLLATE=C sort`
+# - Lines that have a numeric suffix and whose leading prefix
+# matches exactly are sorted according the numeric suffix
+# in increasing numerical order.
+#
+# For example:
+# ~~~
+# tests += \
+# test-a \
+# test-b \
+# test-b1 \
+# test-b2 \
+# test-b10 \
+# test-b20 \
+# test-b100 \
+# # tests
+# ~~~
+# This example shows tests sorted alphabetically, followed
+# by a numeric suffix sort in increasing numeric order.
+#
+# Cleanups:
+# - Tests that end in "a" or "b" variants should be renamed to
+# end in just the numerical value. For example 'tst-mutex7robust'
+# should be renamed to 'tst-mutex12' (the highest numbered test)
+# or 'tst-robust11' (the highest numbered test) in order to get
+# reasonable ordering.
+# - Modules that end in "mod" or "mod1" should be renamed. For
+# example 'tst-atfork2mod' should be renamed to 'tst-mod-atfork2'
+# (test module for atfork2). If there are more than one module
+# then they should be named with a suffix that uses [0-9] first
+# then [A-Z] next for a total of 36 possible modules per test.
+# No manually listed test currently uses more than that (though
+# automatically generated tests may; they don't need sorting).
+# - Avoid including another test and instead refactor into common
+# code with all tests including hte common code, then give the
+# tests unique names.
+#
+# If you have a Makefile that needs converting, then you can
+# quickly split the values into one-per-line, ensure the start
+# and end markers are in place, and then run the script to
+# sort the values.
+
+import sys
+import locale
+import re
+import functools
+
+def glibc_makefile_numeric(string1, string2):
+ # Check if string1 has a numeric suffix.
+ var1 = re.search(r'([0-9]+) \\$', string1)
+ var2 = re.search(r'([0-9]+) \\$', string2)
+ if var1 and var2:
+ if string1[0:var1.span()[0]] == string2[0:var2.span()[0]]:
+ # string1 and string2 both share a prefix and
+ # have a numeric suffix that can be compared.
+ # Sort order is based on the numeric suffix.
+ return int(var1.group(1)) > int(var2.group(1))
+ # Default to strcoll.
+ return locale.strcoll(string1, string2)
+
+def sort_lines(lines):
+
+ # Use the C locale for language independent collation.
+ locale.setlocale (locale.LC_ALL, "C")
+
+ # Sort using a glibc-specific sorting function.
+ lines = sorted(lines, key=functools.cmp_to_key(glibc_makefile_numeric))
+
+ return lines
+
+def sort_makefile_lines():
+
+ # Read the whole Makefile.
+ lines = sys.stdin.readlines()
+
+ # Build a list of all start markers (tuple includes name).
+ startmarks = []
+ for i in range(len(lines)):
+ # Look for things like "var = \", "var := \" or "var += \"
+ # to start the sorted list.
+ var = re.search(r'^([a-zA-Z0-9-]*) [\+:]?\= \\$', lines[i])
+ if var:
+ # Remember the index and the name.
+ startmarks.append((i, var.group(1)))
+
+ # For each start marker try to find a matching end mark
+ # and build a block that needs sorting. The end marker
+ # must have the matching comment name for it to be valid.
+ rangemarks = []
+ for sm in startmarks:
+ # Look for things like " # var" to end the sorted list.
+ reg = r'^ # ' + sm[1] + r'$'
+ for j in range(sm[0] + 1, len(lines)):
+ if re.search(reg, lines[j]):
+ # Rembember the block to sort (inclusive).
+ rangemarks.append((sm[0] + 1, j))
+ break
+
+ # We now have a list of all ranges that need sorting.
+ # Sort those ranges (inclusive).
+ for r in rangemarks:
+ lines[r[0]:r[1]] = sort_lines(lines[r[0]:r[1]])
+
+ # Output the whole list with sorted lines to stdout.
+ [sys.stdout.write(line) for line in lines]
+
+
+def main(argv):
+ sort_makefile_lines ()
+
+if __name__ == '__main__':
+ main(sys.argv[1:])