* Makefile.am (maintainer-check): Refine check for @_ in scalar context. Check for correct use of PRE_INSTALL, NORMAL_INSTALL, POST_INSTALL, PRE_UNINSTALL, NORMAL_UNINSTALL, and POST_UNINSTALL. * lib/am/texinfos.am (uninstall-info-am): Hide the invocation of $(PRE_UNINSTALL).