Starting with Raptor 2.13.0, it is also possible to use Cygwin 1.7 instead of
Cygwin 1.5. Some work was necessary to add support for Cygwin 1.7 due to a
change in command line interface in some of the Cygwin tools.
 
Due to this change in the command line interface, we have had to introduce the
SBS_CYGWIN17 environment variable whose value should be the root directory of
the Cygwin 1.7 installation. We hope this is temporary and that we can remove
this at some point. The following bullet points indicate the order of
precedence of the SBS_CYGWIN and SBS_CYGWIN17 environment variables.
 
* SBS_CYGWIN set,   SBS_CYGWIN17 unset: assume Cygwin 1.5 is being used
* SBS_CYGWIN set,   SBS_CYGWIN17 set:   assume Cygwin 1.7 is being used
* SBS_CYGWIN unset, SBS_CYGWIN17 set:   assume Cygwin 1.7 is being used
 
You will get errors if you set SBS_CYGWIN to be the root of a Cygwin 1.7
installation directory and if SBS_CYGWIN17 is not defined correctly.