--- /dev/null
+/* Make free() preserve errno.
+
+ Copyright (C) 2003, 2006, 2009-2021 Free Software Foundation, Inc.
+
+ This program is free software: you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 3 of the License, or
+ (at your option) any later version.
+
+ This program 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 General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program. If not, see <https://www.gnu.org/licenses/>. */
+
+/* written by Paul Eggert */
+
+#include <config.h>
+
+#include <stdlib.h>
+
+#include <errno.h>
+
+void
+rpl_free (void *p)
+#undef free
+{
+#if defined __GNUC__ && !defined __clang__
+ /* An invalid GCC optimization
+ <https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98396>
+ would optimize away the assignments in the code below, when link-time
+ optimization (LTO) is enabled. Make the code more complicated, so that
+ GCC does not grok how to optimize it. */
+ int err[2];
+ err[0] = errno;
+ err[1] = errno;
+ errno = 0;
+ free (p);
+ errno = err[errno == 0];
+#else
+ int err = errno;
+ free (p);
+ errno = err;
+#endif
+}