src/Makefile.am: update to latest libtool logic #702

Job	Run time
CMake Serial Minimal Build on Linux	57s
CMake Serial With Clawpack Build on Linux	6m 45s
CMake build on MacOS	36m 34s
CMake Serial With GeoClaw Build on Linux	1m 11s
CMake Serial With CudaClaw (CUDA 10.1) Build on Linux	2m 44s
CMake Serial With CudaClaw (CUDA 11.3) Build on Linux	3m 59s
CMake MPI Minimal Build on Linux	1m 25s
CMake MPI With Clawpack Build on Linux	7m 7s
CMake MPI With GeoClaw Build on Linux	1m 54s
CMake MPI With CudaClaw (CUDA 10.1) Build on Linux	3m 48s
CMake MPI With CudaClaw (CUDA 11.3) Build on Linux	4m 57s
CMake MPI With ThunderEgg Build on Linux	3m 28s
	1h 14m 49s

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