--- /dev/null
+/*
+ * SPDX-License-Identifier: GPL-3.0-or-later
+ */
+
+#define _GNU_SOURCE
+
+#include "path-util.h"
+
+#include <limits.h>
+#include <stdlib.h>
+
+
+char *
+notmuch_canonicalize_file_name (const char *path)
+{
+#if HAVE_CANONICALIZE_FILE_NAME
+ return canonicalize_file_name (path);
+#elif defined(PATH_MAX)
+ char *resolved_path = malloc (PATH_MAX + 1);
+ if (resolved_path == NULL)
+ return NULL;
+
+ return realpath (path, resolved_path);
+#else
+#error undefined PATH_MAX _and_ missing canonicalize_file_name not supported
+#endif
+}