to emulate these functions on platforms where one or more of these functions
are not available (PET, CBM-II).
git-svn-id: svn://svn.cc65.org/cc65/trunk@1544 b7a2c559-68d2-44c3-8de9-860c34a00d81
changed/added some comments
all cbm_* IO functions are using _oserror now
git-svn-id: svn://svn.cc65.org/cc65/trunk@682 b7a2c559-68d2-44c3-8de9-860c34a00d81