From 6ef67cff6ba26645f9cbe23ffb401f3d49a66429 Mon Sep 17 00:00:00 2001
From: Simon McVittie <smcv@collabora.com>
Date: Mon, 21 Jan 2019 14:28:24 +0000
Subject: configure.ac: Forbid AX_-prefixed patterns more selectively

We want to make autoconf fail early and with a user-comprehensible
message if autoconf-archive isn't installed, rather than generating
a configure script with syntax errors, or a configure script that runs
successfully but doesn't do what we intended.

However, autoconf-archive doesn't actually guarantee not to use
AX_-prefixed shell variable names without m4_pattern_allow'ing them
(unlike Autoconf, Automake, Libtool and pkg-config, which explicitly use
m4_pattern_allow for variables with AC_, AM_, LT_ and PKG_ prefixes), so
it isn't safe to assume that they won't be used. In particular, recent
versions of AX_CHECK_GNU_MAKE appear to be using
$AX_CHECK_GNU_MAKE_HEADLINE as a shell variable.

Instead, specifically forbid the names of the finite list of macros
that we actually use.

Signed-off-by: Simon McVittie <smcv@collabora.com>
Resolves: dbus#249
(cherry picked from commit ee09cc0acdc1c34e8ae999adf9922f3d0d66f407)
---
 configure.ac | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/configure.ac b/configure.ac
index cc86860..d876a2f 100644
--- a/configure.ac
+++ b/configure.ac
@@ -10,7 +10,7 @@ AC_INIT([dbus],[dbus_version],[https://bugs.freedesktop.org/enter_bug.cgi?produc
 
 AC_CONFIG_AUX_DIR([build-aux])
 
-m4_pattern_forbid([^AX_],
+m4_pattern_forbid([^AX_(CHECK_ENABLE_DEBUG|CODE_COVERAGE|COMPILER_FLAGS|COMPILER_FLAGS_(CFLAGS|CXXFLAGS|LDFLAGS))\b],
   [Unexpanded AX_ macro found. Please install GNU autoconf-archive])
 
 AC_CANONICAL_HOST
-- 
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