Have CMake preprocess all fortran source files #947

Job	Run time
CMake Serial Minimal Build on Linux	1m 14s
CMake build on MacOS	7m 13s
CMake Serial With Clawpack Build on Linux	9m 43s
CMake Serial With Clawpack and HDF Build on Linux	10m 36s
CMake Serial With GeoClaw Build on Linux	3m 59s
CMake Serial With CudaClaw (CUDA 10.1) Build on Linux	3m 27s
CMake Serial With CudaClaw (CUDA 11.3) Build on Linux	3m 33s
CMake MPI Minimal Build on Linux	2m 22s
CMake MPI With Clawpack Build on Linux	8m 40s
CMake MPI With Clawpack and HDF Build on Linux	9m 51s
CMake MPI With GeoClaw Build on Linux	4m 0s
CMake MPI With CudaClaw (CUDA 10.1) Build on Linux	3m 31s
CMake MPI With CudaClaw (CUDA 11.3) Build on Linux	4m 2s
CMake MPI With ThunderEgg Build on Linux	4m 3s
	1h 16m 14s

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