system-info: Always pass around a non-NULL environment block
Instead of calling getenv() if the environment is NULL, we determine what's in the environment on creating the SrtSystemInfo and then pass it around as a parameter.
/cc @denittis
Instead of calling getenv() if the environment is NULL, we determine what's in the environment on creating the SrtSystemInfo and then pass it around as a parameter.
/cc @denittis