Redis: Support for Tcl 9.0 in the Test Suite

Problem

The Redis test suite was incompatible with Tcl 9.0, as some deprecated commands and precision variables were still used in the tests.

Solution

Added 9.0 to the list of versions checked by the runtest script. Updated package require Tcl to accept versions up to 10, and removed obsolete assignments to tcl_precision that caused errors.

Result

The Redis test suite can now run smoothly on modern Linux distributions that ship with Tcl 9.0 by default.

Commit: redis/redis@707757e