Update to TinyScheme 1.39

Changes:

Version 1.39
    Drew Yao fixed buffer overflow problems in mk_sharp_const.
Version 1.38
    Interim release until the rewrite, mostly incorporating modifications from
    Kevin Cozens. Small addition for Cygwin in the makefile, and modifications
    by Andrew Guenther for Apple platforms.
Version 1.37
    Joe Buehler submitted reserve_cells.
Version 1.36
    Joe Buehler fixed a patch in the allocator.
    Alexander Shendi moved the comment handling in the scanner, which
    fixed an obscure bug for which Mike E had provided a patch as well.
    Kevin Cozens has submitted some fixes and modifications which have not
    been incorporated yet in their entirety.

(asau)