Update copyright notes to match recent gnulib-related changes.

Update copyright notes to match recent gnulib-related changes.

* notes/copyright: Add aclocal.m4, m4/*.m4, lib/Makefile.in,
arg-nonnull.h, c++defs.h, compile, depcomp, missing,
warn-on-use.h, lib/*.[ch], lib/gnulib.mk.  Remove src/mktime.c,
lib-src/getopt1.c, lib-src/getopt_int.h (files are now in lib and
are subsumed by the lib/*.[ch] rule).  Remove m4/getopt.m4 (now
subsumed by m4/*.m4 rule).  config.guess, config.sub, and
doc/man/texinfo.tex are now copied in from gnulib.