* Makefile.am: Support the doc sub-directory. We don't have a
COPYRIGHT file.
* src/Makefile.am: Don't prefix the file paths by the absolute
path of the src dir; current autotools know how to deal with it,
otherwise and it break them.
* tests/Makefile.am: Likewise. Make sure to remove the output of
the tests upon make clean.
* Makefile.in: Re-generate.
* aclocal.m4: Likewise.
* configure: Likewise.
* src/Makefile.in: Likewise.
* tests/Makefile.in: Likewise.