Some bugfixes for keygen and keyconvert, discovered by gcc.
Stewart Brodie authored
  Temporary GNUmakefile added containing UNIX build system.
Detail:
  gcc complained about returning the address of a local variable as
    a function result in both keygen and keyconvert.  The two variables
    concerned have now been made static like they should have been.
    Unlikely to have caused much aggravation, but only through luck.
  The Keyboard data structure has been updated to explicitly use an
    unsigned char in some places.  This is necessary for systems on
    which char is signed by default.
  The GNUmakefile is a temporary addition until native tool support can
    be sorted out.  In the xriscos environment, do "make links" and
    then "make rom" to build the module.  "make clean" will remove all
    the built stuff and the symbolic links.  Requires access to the
    exported Unicode library files.  keyconvert is built, but will not
    work for the obvious reason that it calls SWIs.
Admin:
  GNUmakefile will be removed at a later date - it's only temporary.
  Tested - builds the same module (for Keyboard=All, Machine=Phoebe)
    byte-identically.


Version 0.80. Tagged as 'IntKey-0_80'
92fdf5ac