if ((CMAKE_GENERATOR MATCHES "Visual Studio") AND (CMAKE_GENERATOR_TOOLSET STREQUAL ""))
  message(WARNING "Visual Studio generators use the x86 host compiler by default, even for "
                  "64-bit targets.  This can result in linker instability and out of memory"
                  "errors.  To use the 64-bit host compiler, pass -Thost=x64 on the CMake "
                  "command line.")
endif()