Bad dependency in new build system

[trquinn]

Compiling the GPU version, then logging out, then logging back in to recompile, will generate an error like:

make make: *** No rule to make target '/tmp/pbs.7324411.pbspl1.nas.nasa.gov/tmpxft_00013835_00000000-5_HostCUDA.cudafe1.cpp', needed by 'HostCUDA.o'. Stop.

A workaround is to remove the HostCUDA.d file, since it has the dependency on the tmp file.