ooc-980618 & oo2c-1.3.7

[Michael van Acken <KK120y2@mail.lvr.de>]

News:
- some fixes in library modules
- removed SetXXX methods from Channel.Mod and exported the record
  fields of the channel and riders instead; keep in mind that the
user
  not supposed to change the fields, the are exported read/write for
  the sake of extensions
- likewise, for the sake of extensions, the modules TextRider and
  BinaryRider export some things that should not be accessed directly
  by the user
- minor fixes and code cleanup in the compiler code

The changes to Channel.Mod broke the binary interface between the C
code in version 1.3.6 and 1.3.7.  This means that we cannot build an
"Oberon-2 code only" patch for this update :-(

This release also includes the infrastructure for installation of
add-on library packages.  Additionally, I have written some autoconf
macros to access the OOC configuration during installation, to test
for the presence of external libraries, and to add the results to the
installed compiler's initialization file.

Tim's next release of VO will have a configure script that uses all
these features.  VO's "make install" will build a library
automatically whenever possible, and install all necessary files into
the oo2c directory, together with an adjusted initialization file.

-- mva