Remove C++ compiler option '-stdlib=libstdc++'

It breaks compilation under openSusE 12.2 and Centos 6.5:

  Building CXX object
  CMakeFiles/cmTryCompileExec2143522885.dir/testCXXCompiler.cxx.o

  /usr/bin/c++ -Wno-deprecated -stdlib=libstdc++ -o
  CMakeFiles/cmTryCompileExec2143522885.dir/testCXXCompiler.cxx.o -c
  /home/andrew/CAST_NEW/SDF/VisIt/CMakeFiles/CMakeTmp/testCXXCompiler.cxx

  c++: error: unrecognized command line option ‘-stdlib=libstdc++’
Fixed copying of material and obstacle group names.