wishlist - Way to specifiy alternative extension for :if-exists :rename

[mon_key]

wishlist - A Way to specifiy alternative extension for :if-exists :rename
A way to query the rename pathname that SBCL will generate

Right now if i have an existing file foo.gz and i'm using salza2/chipz and with-open-file and foo.gz exists I'll get foo.gz.bak
CL can likely handle access to this file fine but the cli balks e.g.:
shell> gunzip foo.gz.bak

[Nikodemus Siivola (nikodemus)]

Simplest way would be to add SB-EXT:*RENAME-SUFFIX* or similar, but I think the moral equivalent of COMPILE-FILE-PATHNAME should also be provided.

Or maybe allow :IF-EXISTS '(:RENAME #p"my-backups/") or similar.