title: AC_CONFIG_MACRO_DIRS([build-aux/m4]) conflicts with ACLOCAL.AMFLAGS=-I build-aux/m4
body: <p>On Windows Cygwin make of some program gives</p>
  
  <pre><code>libtoolize: putting auxiliary files in AC_CONFIG_AUX_DIR, 'build-aux'.
  libtoolize: copying file 'build-aux/ltmain.sh'
  libtoolize:   error: AC_CONFIG_MACRO_DIRS([build-aux/m4]) conflicts with ACLOCAL.AMFLAGS=-I build-aux/m4
  </code></pre>