Version 4.1 of SunOS claims to be making strides towards SVR4 compatibility.
Under previous releases of SunOS the definitions od to{upper,lower} were
found in /usr/include/ctype.h. However under SunOS 4.1.1 these definitions
are found in /usr/include/pcfs/pc_dir.h. Is this compatible with SVR4? I
don't think so, however I may be wrong.