update_asyncio.sh: Make target python dir configurable

Author: 1st1

update_asyncio.sh

@@ -1,5 +1,18 @@
-PYTHON=${PYTHON:-~/prog/python/default}
-ASYNCIO=${ASYNCIO:-.}
+#!/bin/bash
+
+PYTHON=${1-$HOME/cpython}
+
+if [ ! -d $PYTHON ]
+then
+    echo Bad destination $PYTHON
+    exit 1
+fi
+
+if [ ! -f asyncio/__init__.py ]
+then
+    echo Bad current directory
+    exit 1
+fi
 
 echo "Sync from $PYTHON to $ASYNCIO"
 set -e -x