I have set ACLOCAL_PATH to /usr/share/aclocal which contains pkg.m4 that is required for a package a would like to compile. However, simply running autoreconf --install --force doesn't pick up pkg.m4. Only if /usr/share/aclocal is specified via the -I flag pkg.m4 is picked up.
$ autoreconf --version autoreconf (GNU Autoconf) 2.69 Copyright (C) 2012 Free Software Foundation, Inc. License GPLv3+/Autoconf: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>, <http://gnu.org/licenses/exceptions.html> This is free software: you are free to change and redistribute it. There is NO WARRANTY, to the extent permitted by law. Written by David J. MacKenzie and Akim Demaille. $ echo $ACLOCAL_PATH /usr/share/ac $ autoreconf --install --force libtoolize: putting auxiliary files in AC_CONFIG_AUX_DIR, `build-aux'. libtoolize: copying file `build-aux/ltmain.sh' libtoolize: putting macros in AC_CONFIG_MACRO_DIR, `m4'. libtoolize: copying file `m4/libtool.m4' libtoolize: copying file `m4/ltoptions.m4' libtoolize: copying file `m4/ltsugar.m4' libtoolize: copying file `m4/ltversion.m4' libtoolize: copying file `m4/lt~obsolete.m4' configure.ac:86: error: possibly undefined macro: AC_MSG_WARN If this token and others are legitimate, please use m4_pattern_allow. See the Autoconf documentation. autoreconf: /usr/local/GNU/autoconf-2.69/bin/autoconf failed with exit status: 1 $ autoreconf --install --force -I /usr/share/aclocal libtoolize: putting auxiliary files in AC_CONFIG_AUX_DIR, `build-aux'. libtoolize: copying file `build-aux/ltmain.sh' libtoolize: putting macros in AC_CONFIG_MACRO_DIR, `m4'. libtoolize: copying file `m4/libtool.m4' libtoolize: copying file `m4/ltoptions.m4' libtoolize: copying file `m4/ltsugar.m4' libtoolize: copying file `m4/ltversion.m4' libtoolize: copying file `m4/lt~obsolete.m4' aclocal was compiled from source by my system administrator: ➜ pyflame git:(master) ✗ aclocal --print-ac-dir /usr/local/GNU/automake-1.15/share/aclocal