Log Message:
Update buildtool to 0.7.

Changes in 0.7, state: alpha
----------------------------

    * New check bt_check_bits, which determines appropiate C types for
      different sizes.

    * New  check bt_check_hdr_std,  which  searches standard  headers.
      You *must* use this function,  as it is now required for further
      checks (improves portability).

    * Addition of the `siteinfo' target to the main program. It allows
      to get  specific information about where  Buildtool is installed
      by third party programs.

    * Default name  of Makefile's changed to  Makefile.bt. This allows
      Automake and Buildtool  to coexist in the same  package and also
      avoids  running  a regular  Make  tool  within a  Buildtool-ized
      package (which will confuse the user).

    * Build fixes under MacOS X (Darwin).

    * Minor bug fixes to run cleanly under Win32, using Cygwin.

    * Runtime fixes under GNU-based  systems (the `getopt' command did
      not behave properly).

While I'm here, fix some things: force the package to use TeXinfo 4.0 and
make it use PKG_SYSCONFDIR.