Slow compilation speed

[RubenVerborgh]

This library (re-)compiles very slowly compared to other libraries. I wonder if we can find causes/fixes for that. Perhaps some of the header files are doing overly complex things?

[artob]

Certainly the header file structuring and inclusions could be cleaned up a lot, it's a bit haphazard at the moment.

[donpellegrino]

I am not seeing any particular compilation step standing out as slow. For reference I am seeing ~30 seconds of wall-clock time for a full parallel build of hdt-cpp (excluding the hdt-it GUI):

make -j
<snip>
real	0m28.372s
user	3m20.095s
sys	1m19.879s

Test System CPU: Intel(R) Xeon(R) Gold 6128 CPU @ 3.40GHz Compiler: Intel(R) oneAPI DPC++/C++ Compiler 2022.0.0 (2022.0.0.20211123) Memory: 188 GB

A next step might be to collect timing for each compiler command to see if some stand out as particularly slow.