Unable to run Geos on Pangea 3 with shared libraries

[acitrain]

Describe the bug
Since the merge of PR #3282 we are unable to run GEOS on Pangea3 due to issue on a powerpc architecture to run with shared libraries. We get the follopwing error at the execution:

geos: error while loading shared libraries: libmainInterface.so: cannot open shared object file: No such file or directory

And sometimes we are unable to compile (error at the link edition)

Platform (please complete the following information):

• Machine Pangea 3
• Compiler gcc/8.4.1

[Algiane]

Only the pygeosx.so shared library is installed in the $CMAKE_INSTALL_PREFIX/lib directory so the other shared libraries against which is built pygeosx are not found.
It can be solved:

• by adding the path toward the other libs to the LD_LIBRARY_PATH variable (so the build directory). It is not clean and not usual as it means that the build directory cannot be deleted without breaking the runtime;
• by installing all the shared libs in the same location (usual way)

[rrsettgast]

The install command was accidentally removed. I will create a quick patch.

[acitrain]

Thanks Randy!

I'll close my PR linked with this issue when the patch will be operational