to ...
* Makefile.am, doc-gnome/Makefile.am, pc/Makefile.am: ... this
* Make.common.in: support for "distdir" for compatability
with Automake-generated makefiles
* autogen.sh: run automake. Force cache - it is off by default
in autoconf 2.49a, but it's still handy for maintainers
* configure.in: adapted for Automake
