This avoids use of an uninitialized value in the KWSys ProcessUNIX
polling implementation when no timeout is given.

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.

The kwsysPrivate header double-inclusion check hits a false positive on
VMS for an undetermined reason.  This simplifies the workaround and
documents it.

Read-only directories must be given write permission before we can
remove files and subdirectories from them.

ENH: check in almost building VMS stuff with VMSBuild directory since the bootstrap script will not work on VMS

Alex

This removes SystemTools::FileExistsInParentDirectories from KWSys since
it is a special-purpose method that is not generally useful.

When SystemTools::GetParentDirectory was fixed to never remove the root
path component from a full path we violated an assumption made by
IsSubDirectory that eventually GetParentDirectory returns an empty
string.  This led to an infinite loop if the potential parent directory
is empty, so we explicitly avoid that case.

The previous change to this method broke cases where the input path does
not exist.  The SystemTools::GetParentDirectory method is redundant with
the more robust SystemTools::GetFilenamePath.  This replaces its
implementation to just call GetFilenamePath.

BUG: SystemTools::GetParentDirectory() will crash if "/" is passed in as argement. Valid check is added to make sure the input argment exists, and if "/" is passed in, empty string will be returned.

All KWSys C symbol names begin with the KWSYS_NAMESPACE defined at
configuration time.  For ease of editing we write canonical names with
the prefix 'kwsys' and use macros to map them to the configured prefix
at preprocessing time.  In the case of standalone KWSys, the prefix is
'kwsys', so the macros were previously defined to their own names.

We now skip defining the macros in the identity case so that the final
symbol names are never themselves macros.  This will allow the symbols
to be further transformed behind the scenes to help linkers in special
cases on some platforms.

Previously KWSys SystemInformation parsed this file assuming a strict
order and set of fields, but the order is not reliable.  This
generalizes the implementation to support any order and extra fields.

BUG: comment out faulty seekp which make kwsys::*stringstream fails on platform with no std::*stringstream implementation

STYLE:Empty commit just add information about rev 1.15: the reason is that long is 64-bit on gcc on Linux because it uses the LP64 data model whereas long is 32-bit on VS 64-bit because it uses the LLP64 model (ref: http://en.wikipedia.org/wiki/64-bit#64-bit_data_models )

COMP:Fix warning on VS 64bit. Don't why gcc 4.3.2 didn't catch this one on a 64bit machine with -Wconversion on.

COMP:Fixed gcc 4.3.2 warning with -O1 and above: ignoring return value of read'), declared with attribute warn_unused_result