1 files changed, 46 insertions, 0 deletions
diff --git a/m4/00gnulib.m4 b/m4/00gnulib.m4
new file mode 100644
index 0000000..bd24796
--- /dev/null
+++ b/m4/00gnulib.m4
@@ -0,0 +1,46 @@
+# 00gnulib.m4 serial 3
+dnl Copyright (C) 2009-2018 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 This file must be named something that sorts before all other
+dnl gnulib-provided .m4 files.  It is needed until such time as we can
+dnl assume Autoconf 2.64, with its improved AC_DEFUN_ONCE and
+dnl m4_divert semantics.
+
+# Until autoconf 2.63, handling of the diversion stack required m4_init
+# to be called first; but this does not happen with aclocal.  Wrapping
+# the entire execution in another layer of the diversion stack fixes this.
+# Worse, prior to autoconf 2.62, m4_wrap depended on the underlying m4
+# for whether it was FIFO or LIFO; in order to properly balance with
+# m4_init, we need to undo our push just before anything wrapped within
+# the m4_init body.  The way to ensure this is to wrap both sides of
+# m4_init with a one-shot macro that does the pop at the right time.
+m4_ifndef([_m4_divert_diversion],
+[m4_divert_push([KILL])
+m4_define([gl_divert_fixup], [m4_divert_pop()m4_define([$0])])
+m4_define([m4_init],
+  [gl_divert_fixup()]m4_defn([m4_init])[gl_divert_fixup()])])
+
+
+# AC_DEFUN_ONCE([NAME], VALUE)
+# ----------------------------
+# Define NAME to expand to VALUE on the first use (whether by direct
+# expansion, or by AC_REQUIRE), and to nothing on all subsequent uses.
+# Avoid bugs in AC_REQUIRE in Autoconf 2.63 and earlier.  This
+# definition is slower than the version in Autoconf 2.64, because it
+# can only use interfaces that existed since 2.59; but it achieves the
+# same effect.  Quoting is necessary to avoid confusing Automake.
+m4_version_prereq([2.63.263], [],
+[m4_define([AC][_DEFUN_ONCE],
+  [AC][_DEFUN([$1],
+    [AC_REQUIRE([_gl_DEFUN_ONCE([$1])],
+      [m4_indir([_gl_DEFUN_ONCE([$1])])])])]dnl
+[AC][_DEFUN([_gl_DEFUN_ONCE([$1])], [$2])])])
+
+# gl_00GNULIB
+# -----------
+# Witness macro that this file has been included.  Needed to force
+# Automake to include this file prior to all other gnulib .m4 files.
+AC_DEFUN([gl_00GNULIB])