g.gui.gcp: launch GUI in the background

git-svn-id: https://svn.osgeo.org/grass/grass/trunk@57373 15284696-431f-4ddb-bdfa-cd5b030d7da7

gui/wxpython/gcp/g.gui.gcp.py

@@ -73,4 +73,8 @@ def main():
 
 
 if __name__ == '__main__':
-    main()
+    # launch GUI in the background
+    child_pid = os.fork()
+    if child_pid == 0:
+        main()
+    os._exit(0)