New macros.
- configure.in, include/cl_config.h.in (CL_VERSION, CL_VERSION_MINOR,
CL_VERSION_PATCHLEVEL): New definitions.
- autoconf/config.guess, autoconf/config.sub, autoconf/ltconfig,
autoconf/ltmain.sh: updated from FSF (libtool 1.3.5, etc).
- src/Makefile.in, configure.in: release-variables renamed from
CLN_* to CL_*.
- configure.in: default to build both shared and static library
(i.e. default to the most common behaviour).