[eCAL Sys] Allow picking up hostname in Sys configs

[git-pi-e]

Context

In eCAL Sys, only the Executable, Arguments and Working dir fields allow using variables.
Is there a way to set the Host field to $HOST{HOSTNAME} as well, so that if a .ecalsys config is created, it can be run on any PC?

[KerstinKeller]

Hi @git-pi-e, this sounds like a reasonable request. Right now we're busy with eCAL 6 Release, but it might be something we'll consider for further improvements for later eCAL Releases.