[GRASS5] 5.0: CXX support added - r.terraflow

[Markus Neteler]

Hi,

I have just submitted a change to configure[.in] to
optionally support CXX:
--with-cxx

added r.terraflow to the list of optional modules and
changed it's Gmakefile to use $(CXX).

I hope I did it right.
Please try and fix directly in CVS, if needed.

Cheers

 Markus

PS: If ok, may it go into 5.0.2 ?