Is your feature request related to a problem? Please describe.

I want gClingOpts->AllowRedefinition = 1; to be the default behavior. Often I forget to turn it on for my REPL session, and then when I do it's too late (can't redefine things defined prior to switching that option it seems).

Describe the solution you'd like

I'd like something like a ~/.config/cling.conf or similar, where I can put these configurations to be evaluated automatically when Cling runs.

Alternative solution considered

Perhaps AllowRedefinition's default value simply should be 1? I can't think of a useful use case to have it prevent someone from redefining a variable in such a dynamic environment as a REPL.