[Cython] --cplus option to the "cython" command line script

[Martin C. Martin]

Hi,

the --cplus option doesn't appear in the usage, and the comments in the 
code say its only supported on MacOS X.  But that isn't true, it's used 
by the distutils when you specify langauge="c++".

Can it be added to the usage in Cython/Compiler/CmdLine.py ?

Best,
Martin