> While Windows is the only major platform which doesn't have a POSIX
> shell, it is on the other hand the platform which has like 80 or 90%
> market share. So one could also say "only 10 to 20% of installed systems
> have a POSIX shell".
On the third hand, there is a POSIX shell, and build tools based on it, available for
approximately 100% of these. They aren't necessarily installed by default (many Linux systems
don't have a C compiler by default either these days), but developers are more than capable of
installing a software package for this purpose.