In particular, the gnulib-tool utility now maintains lib/Makefile.am, as
well as many files in the m4 and lib directories. The file
m4/gnulib-cache.m4 allows the Gnulib files to be refreshed. See
http://www.gnu.org/software/gnulib/.
Rewrite the input to autoconf: add the definition of PACKAGE_AUTHOR,
add checks for Standard C and for C compiler warnings (via the file
m4/ax_cflags_warn_all.m4 from the GNU Autoconf Archive), rearrange
various macros and the order of Makefile creation.