* autoconf/aclocal.m4: upgrade to autoconf-2.52 infrastructure,
sync with CLisp from CVS.
* autoconf/autoconf: Likewise.
* autoconf/autoconf.m4f: Likewise (new file).
* configure.ac: Likewise (new file, replaces configure.in).
* configure.in: Likewise (deleted, replaced by configure.ac).
* autoconf/config.{guess,sub}: Update to GNU version 2001-12-13.
* src/Makefile.in: made VPATH safe for autoconf-2.52.
* include/cln/config.h.in: Add __s390__.
_FPU_IEEE is really defined.
* include/cln/modules.h: change assembler labels from `label' to
`label:' on hppa, needed by Linux (see comment).
* autoconf/acinclude.m4: new file (for storing CLN-specific macros).
* Makefile.devel: adjusted.
* autoconf/aclocal.m4: regenerate.
* src/base/low/cl_low_mul.cc: moved POD variables that are declared
extern "C" elsewhere out of the namespace.
* src/base/low/cl_low_div.cc: Likewise.