* Makefile.am (maintainer-check): Don't check for 'cd' calls in m4.

* Makefile.am (maintainer-check): Don't check for 'cd' calls in m4.
* lib/am/tags.am (GTAGS): Use $(am__cd) instead of 'CDPATH=: && cd'.
* lib/am/dejagnu.am (check-DEJAGNU): Likewise.
* lib/am/distdir.am (distcheck): Likewise.
* lib/am/texinfos.am (install-info-am, dist-info): Rewrite without
using cd so we don't have to fiddle with CDPATH.
* lib/am/header-vars.am (am__cd): Define so as to support Zsh and
DOSish path separator.