Create the cli.gitignore mechanism to pass extra default cli options

Document that X11 mouse is not moving.

Convert x='' to x= on all scripts, and also fix case ;; indentations.

Add dummy value to QEMU's -trace enable= to prevent warning.

Expand built-in package choice rationale.

rungdbserver

@@ -1,6 +1,7 @@
 #!/usr/bin/env bash
 set -eu
 . common
+set -- ${cli_rungdbserver:-} "$@"
 arch='x86_64'
 gem5=false
 while getopts a:g OPT; do