Add _GLIBCXX_USE_TBB_PAR_BACKEND=0 definition to allow compilation wi…

…th libstdc++10 without it trying to use old TBB API

build.sh

@@ -48,7 +48,8 @@ export CMAKE_OSX_DEPLOYMENT_TARGET="${MACOSX_DEPLOYMENT_TARGET}"
 export DUNE_COPASI_USE_STATIC_DEPS=ON
 export CMAKE_INSTALL_PREFIX=$DEPSDIR
 export MAKE_OPTIONS="-j2 VERBOSE=1"
-export CMAKE_CXX_FLAGS="'-fvisibility=hidden'"
+# disable gcc 10 pstl TBB backend as it uses the old TBB API
+export CMAKE_CXX_FLAGS="'-fvisibility=hidden -D_GLIBCXX_USE_TBB_PAR_BACKEND=0'"
 export BUILD_SHARED_LIBS=OFF
 export CMAKE_DISABLE_FIND_PACKAGE_MPI=ON
 export DUNE_ENABLE_PYTHONBINDINGS=OFF