[libxslt] Set AC_CONFIG_MACRO_DIR

[Nick Wellnhofer <nwellnhof src gnome org>]

commit bbe530082631041c62e86b1f8054b399898c5a87
Author: Nick Wellnhofer <wellnhofer aevum de>
Date:   Sat Apr 2 17:21:40 2022 +0200

    Set AC_CONFIG_MACRO_DIR
    
    Silences libtool warnings.

 .gitignore   | 1 +
 Makefile.am  | 2 ++
 configure.ac | 1 +
 3 files changed, 4 insertions(+)
---
diff --git a/.gitignore b/.gitignore
index 3b18ae23..18e56a2d 100644
--- a/.gitignore
+++ b/.gitignore
@@ -35,6 +35,7 @@ libxslt.spec
 libxslt.spec.in.orig
 libxslt/xsltconfig.h
 ltmain.sh
+m4/
 missing
 py-compile
 python/*.pyc
diff --git a/Makefile.am b/Makefile.am
index e3746dfb..d5d6a4cf 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -1,3 +1,5 @@
+ACLOCAL_AMFLAGS = -I m4
+
 SUBDIRS = libxslt libexslt xsltproc doc tests
 if WITH_PYTHON
 SUBDIRS += python
diff --git a/configure.ac b/configure.ac
index 03391d35..81930b00 100644
--- a/configure.ac
+++ b/configure.ac
@@ -8,6 +8,7 @@ m4_define([MICRO_VERSION], [35])
 AC_INIT([libxslt], [MAJOR_VERSION.MINOR_VERSION.MICRO_VERSION])
 AC_CONFIG_SRCDIR([libxslt/xslt.c])
 AC_CONFIG_HEADERS(config.h)
+AC_CONFIG_MACRO_DIR([m4])
 AC_CANONICAL_HOST
 AC_USE_SYSTEM_EXTENSIONS