* gnu/packages/display-managers.scm (lightdm): Update to 1.30.0-0.b7fc321. [source]: Use git. [configure-flags]: Add CFLAGS=-Wno-error=missing-prototypes. [phases]: Delete trailing #t. {fix-paths}: Use search-input-file. [inputs]: Add coreutils. [native-inputs]: Use new style. Replace python-2 by python-wrapper and python2-pygobject by python-pygobject. Add autoconf, automake, gtk-doc, libtool, which and yelp-tools.