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

[Glynn Clements]

Markus Neteler wrote:

> 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.

I've made some changes:

1. Only call AC_PROG_CXX if --with-cxx is used, as failure to find a
working C++ compiler may cause the configure script to fail
altogether.

2. Add entry for CXX to src/CMD/head/head.in.

3. Add entry for COMPILE_FLAGS_CXX to src/CMD/head/head.in.

4. Add definition for CXXFLAGS to src/CMD/generic/make.mid and
mk/mid.mk.

5. Change src/CMD/generic/gmake.sh to use $(CXXFLAGS) instead of
$(CFLAGS) for .cc files.

6. Add @CPPFLAGS@ to the definitions of COMPILE_FLAGS[_CXX] (not
specific to C++).

The r.terraflow Gmakefiles will need to be fixed, as:

a) they use $(CFLAGS) instead of $(CXXFLAGS), and
b) they use -Wall, which is gcc-specific.

> PS: If ok, may it go into 5.0.2 ?

The changes should be harmless; so long as --with-cxx isn't used,
nothing should be affected.

-- 
Glynn Clements <glynn.clements at virgin.net>