SystemTools: Fix compilation with Open Watcom
SystemTools: Fix compilation with Open Watcom

Use ISO C header <wctype.h> for towupper instead of relying on the
MS-specific location of towupper in <ctype.h>

Change-Id: If779418eb6752e7b059bcb9e823f64914b4fa101

chuckatkins/KWSys,chuckatkins/KWSys,chuckatkins/KWSys,chuckatkins/KWSys