From 0ca438ccb5be259ea4de422a0f2d9aba56490e16 Mon Sep 17 00:00:00 2001
From: Nicola Fontana <ntd@entidi.it>
Date: Thu, 21 Oct 2021 12:41:03 +0200
Subject: [PATCH] Fix #16: explicitely check for pkg-config macros

Without this patch, `./bootstrap` fails with the following error if
pkgconf/pkg-config is not installed:

    lib/Makefile.am:76: error: 'pkgconfig_DATA' is used but 'pkgconfigdir' is undefined

This can be triggered by disinstalling `pkgconf/pkg-config`. The problem
here is that the check for `pkg-config` is done at configure level but
`automake` fails at bootstrap level because of the above error.

This basically "fixes" the issue by changing the way in which
`./bootstrap` fails.
---
 configure.ac | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/configure.ac b/configure.ac
index bd498c51..3df29563 100644
--- a/configure.ac
+++ b/configure.ac
@@ -38,8 +38,9 @@ AC_CONFIG_HEADERS([config.h])
 AC_CONFIG_SRCDIR([config.h.in])
 AC_CONFIG_MACRO_DIR([m4])
 AC_PROG_SED
-PKG_PROG_PKG_CONFIG
-PKG_INSTALLDIR()
+m4_ifndef([PKG_INSTALLDIR], [m4_fatal([pkgconf or pkg-config not found or too old (`pkg-config --version` must be >= 0.27)])])
+PKG_PROG_PKG_CONFIG(0.27)
+PKG_INSTALLDIR
 
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