bindist targets to be more standard.
* config.guess: Update with the currently published file.
* config.sub: ditto.
* configure.in: Use value of build_alias instead of testing for
directory names to set BUILDENV.
* configure: ditto.
* lib/Makefile.in: Change the name of the targets install,
install-headers and install-libraries to xinstall, xinstall-headers
and xinstall-libraries for system target specified installation.
Recreate targets install, install-headers and install-libraries for
exec-prefix specified installation. Ditto for the uninstall targets of
the same name.
