cmake HAVE_IBMBGP examples

m-a-d-n-e-s-s/madness CMakeLists.txt :409 

check_cxx_source_compiles(
    "
    #ifndef __bgp__
    #error choke me
    #endif
    int main() { return 0; }
    " HAVE_IBMBGP)

m-a-d-n-e-s-s/madness src/madness/tensor/CMakeLists.txt :73 

elseif (HAVE_IBMBGP)