I went with the shorter license notice used by src/libvirt.c,
rather than spelling out the full LGPLv2+ clause into each of
these files.
* configure.ac: Declare copyright.
* all Makefile.am: Likewise.
* cfg.mk: use $(srcdir)/ prefix for Makefile.nonreentrant include
* examples/domain-events/events-c/Makefile.am tools/Makefile.am
examples/hellolibvirt/Makefile.am: extend the include paths to
use $(top_srcdir)/include too.