live-guile.sh: Export INSIDE_EMACS before launching Guile REPL.

Changing certain values in a .guile file breaks the Geiser REPL. The workaround to this is checking if the INSIDE_EMACS environment variable is set and avoiding breaking changes if it is - this is what the default Guix .guile file does to make sure readline and colorization are available as well as Geiser. However, when launching Guile as done in this script, rather than through Emacs itself, this variable is not set, leading to a broken prompt with such customizations. This patch simply adds that variable to ensure Geiser and .guile files will play nicely.

changed milestone to %0.12 Release

requested review from @tsyesika

This looks good, thanks!

Interesting side node:

Apparently geiser doesn't officially support the use-case of coloured prompts, however this works and seems like a good quality of life improvement so I think we could add it to our live-guile hacking script.

mentioned in commit e87d44ed

merged