The KWSys String implementation of strcasecmp initialized 'result'
immediately before assigning to it. Borland produces a warning in this
case, so this commit removes the extra initialization.
The Compaq compiler (on VMS) includes 'String.c' in source files that
use the stl string while looking for template definitions. This was the
true cause of double-inclusion of the 'kwsysPrivate.h' header. We work
around the problem by conditionally compiling the entire source file on
a condition only true when really building the source.