"Professional CMake" book suggest the following:
"Targets should build successfully with or without compiler support for precompiled headers. It
should be considered an optimization, not a requirement. In particular, do not explicitly include a
precompile header (e.g. stdafx.h) in the source code, let CMake force-include an automatically
generated precompile header on the compiler command line instead. This is more portable across
the major compilers and is likely to be easier to maintain. It will also avoid warnings being
generated from certain code checking tools like iwyu (include what you use)."
Therefore, removed the "#include <PreCompiled.h>" from sources, also
there is no need for the "#ifdef _PreComp_" anymore
Before that (e.g. on MacBook Pro) it was very hard to see the microscopic selection-circle hidden behind much bigger cursor arrow when trying to snap e.g. a line to some vertex. Now this setting can be used for such displays to increase the marker size and make it clearly visible behind the cursor.
The already existing "sketcher marker size" property is intended to be used for sketcher only, so it's not suitable for global setup of all the markers' sizes uniformly...
