diff --git a/libbuild2-autoconf/libbuild2/autoconf/checks/HAVE_ERRNO_H.h b/libbuild2-autoconf/libbuild2/autoconf/checks/HAVE_ERRNO_H.h
new file mode 100644
index 0000000..2928567
--- /dev/null
+++ b/libbuild2-autoconf/libbuild2/autoconf/checks/HAVE_ERRNO_H.h
@@ -0,0 +1,19 @@
+// HAVE_ERRNO_H : BUILD2_AUTOCONF_LIBC_VERSION
+
+#ifndef BUILD2_AUTOCONF_LIBC_VERSION
+#  error BUILD2_AUTOCONF_LIBC_VERSION appears to be conditionally included
+#endif
+
+#undef HAVE_ERRNO_H
+
+/* Since Linux/glibc 2.1, OpenBSD 2.0, FreeBSD 1.0, NetBSD 1.0, Mac OS
+ * and win32.
+ */
+#if BUILD2_AUTOCONF_GLIBC_PREREQ(2, 1) || \
+    BUILD2_AUTOCONF_FREEBSD_PREREQ(1, 0) || \
+    BUILD2_AUTOCONF_OPENBSD_PREREQ(199610) || \
+    BUILD2_AUTOCONF_NETBSD_PREREQ(1, 0) || \
+    defined(BUILD2_AUTOCONF_MACOS) || \
+    defined(_WIN32)
+#  define HAVE_ERRNO_H 1
+#endif