[Paraview] MPI Compilation Flags

[Sean Ziegeler]

At one time I didn't mind looking through, e.g., an "mpicxx" script, to 
figure out the flags to compile MPI programs for a given platform.  That 
is getting harder and harder to do now.  I did it for IBM AIX, but 
recently I've been trying to build MPI-enabled ParaView on a Cray XT4, 
and the scripts are very involved.  Worse, in some versions of OpenMPI 
for Linux, mpicc/mpicxx are executables that read from driver files.

Yet, I can't simply use ... CC=mpicc CXX=mpicxx ccmake ... because the 
intermediate executables for parsing and generating code must be built 
for serial execution.

So what about some options to specify MPI compilers instead of or in 
addition to MPI_LIBRARY, etc.?  I could probably work on the CMake 
scripts to implement this myself, but don't want to if there are major 
objections to that approach.  Or, if someone is already planning on 
doing this, I'd love to know as it would save me _lots_ of time.

Thanks,
Sean