diff --git a/tools/build/cross-build/include/linux/sys/wait.h b/tools/build/cross-build/include/linux/sys/wait.h
index 2721218a83d4..ca17bfae9b8a 100644
--- a/tools/build/cross-build/include/linux/sys/wait.h
+++ b/tools/build/cross-build/include/linux/sys/wait.h
@@ -1,31 +1,47 @@
 /*-
  * SPDX-License-Identifier: BSD-2-Clause
  *
  * Copyright 2021 Jessica Clarke <jrtc27@FreeBSD.org>
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
  *    documentation and/or other materials provided with the distribution.
  *
  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  * SUCH DAMAGE.
  */
 
 #pragma once
 
+/*
+ * glibc's sys/wait.h and stdlib.h both define various wait-related constants,
+ * depending on __USE_XOPEN(2K8) and if the other header has been included.
+ * Since they each probe the other's include guard to determine that, there is
+ * a window between a header defining its include guard and checking for the
+ * other's within which, if the other is included for the first time, they both
+ * believe the other has already defined the relevant macros etc, and so
+ * neither ends up doing so. This was not previously hit, and is still not hit
+ * when using glibc normally (though seems extremely fragile). However, as of
+ * glibc 2.34, signal.h, included by sys/wait, includes a new bits/sigstksz,
+ * which in turn includes unistd.h (when _SC_SIGSTKSZ_SOURCE is defined, which
+ * is implied by _GNU_SOURCE), which we wrap and include stdlib.h from,
+ * creating the exact aforementioned situation that breaks. Thus, forcefully
+ * include stdlib.h first whenever sys/wait.h is as a workaround, since that
+ * way round still works.
+ */
 #include <stdlib.h>
 #include_next <sys/wait.h>