Suppress warning from cmake about policy changes. I'm uncertain

whether the OLD behavior or the NEW behavior was intended.  Either
should be sufficient to suppress the warning, and OLD appears to work.

See: "cmake --help-policy CMP0054" in a more current cmake for a more
detailed explanation of the change.

cmake/run_nvcc.cmake

@@ -88,6 +88,7 @@ endif()
 # and other return variables are present after executing the process.
 macro(cuda_execute_process status command)
   set(_command ${command})
+  cmake_policy(SET CMP0054 OLD)
   if(NOT _command STREQUAL "COMMAND")
     message(FATAL_ERROR "Malformed call to cuda_execute_process.  Missing COMMAND as second argument. (command = ${command})")
   endif()