Consumers of VTK-m when enabling of dropping of unused functions
will see VTK-m functions dropped. Previously this didn't happen
as VTK-m didn't build object files with the correct flags for this.
By allowing the linker to remove unused symbols we see a significant
saving the file size of VTK-m tests, examples, and benchmarks.
An OpenMP build of the tests and benchmarks goes from 168MB to
141MB which is roughly a 16% filesize reduction.
Initially I had presumed that these changes would increase link times.
But in measurements the total wall time for compilation of VTK-m has
stayed about the same ( seeing a decrease of 1.5% ). Presumably the
increased computation is offset by the reduction in file writing.
When both examples and tests are on, there are a few tests created that
will install VTK-m and build the example against the install to make
sure that all expected components are installed. Since it requires the
full compile of a VTK-m application (and some VTK-m applications can
take a while to compile), increase the timeout for these tests.
The timeout is currently set to 10 minutes (600 seconds).
The VTK-m testing infrastructure isn't public facing so it doesn't
need to be installed or clutter the main VTKmWrappers file.
At the same time I have refactored the code to make it clearer
to understand, and remove unused options.
We now have a couple of the examples also being built against
the installed version of VTK-m as a test. This allow us to verify
that VTK-m installs and can be found properly.
