setup BISON_PKGDATADIR and M4 environment variables by the build scripts already for MSVC build

set BISON_PKGDATADIR=C:\RosBE\2.2.1\share\bison

set M4=C:\RosBE\2.2.1\Bin\m4.exe

is needed to be set up manually to succeed compilation for the MSVC build-prompt since we enabled BISON as a requirement during 0.4.15-dev'ing.

Contrary The GCC build via RosBE-prompt does set up that automatically already.

According to ThFabba also the configure VSSolution does set it up automatically already (I did not double-check).

Without having that set up, the configure step for MSVC builds from MSVC build prompt will fail like that.
Here are 2 pictures from VS2019 failing:
oleg1.png
oleg2.png

We should finish that before releasing 0.4.15.