diff --git a/unix/m4/intmax.m4 b/unix/m4/intmax.m4
new file mode 100644
index 0000000..d99c999
--- /dev/null
+++ b/unix/m4/intmax.m4
@@ -0,0 +1,30 @@
+# intmax.m4 serial 2 (gettext-0.14.2)
+dnl Copyright (C) 2002-2005 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+dnl From Bruno Haible.
+dnl Test whether the system has the 'intmax_t' type, but don't attempt to
+dnl find a replacement if it is lacking.
+
+AC_DEFUN([gt_TYPE_INTMAX_T],
+[
+  AC_REQUIRE([gl_AC_HEADER_INTTYPES_H])
+  AC_REQUIRE([gl_AC_HEADER_STDINT_H])
+  AC_CACHE_CHECK(for intmax_t, gt_cv_c_intmax_t,
+    [AC_TRY_COMPILE([
+#include <stddef.h>
+#include <stdlib.h>
+#if HAVE_STDINT_H_WITH_UINTMAX
+#include <stdint.h>
+#endif
+#if HAVE_INTTYPES_H_WITH_UINTMAX
+#include <inttypes.h>
+#endif
+], [intmax_t x = -1;], gt_cv_c_intmax_t=yes, gt_cv_c_intmax_t=no)])
+  if test $gt_cv_c_intmax_t = yes; then
+    AC_DEFINE(HAVE_INTMAX_T, 1,
+      [Define if you have the 'intmax_t' type in <stdint.h> or <inttypes.h>.])
+  fi
+])