common: factor out common opts to all scripts

qemu-trace2txt

@@ -1,9 +1,9 @@
 #!/usr/bin/env bash
 . "$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)/common"
-while getopts a: OPT; do
+while getopts "${common_getopts_flags}" OPT; do
   case "$OPT" in
-    a)
-      common_arch="$OPTARG"
+    ?)
+      common_getopts_case "$OPT"
       ;;
   esac
 done