How to set the lib-directory when running gpg-1.0.7?

[Helmut Waitzmann]

In the manual page, I can read

   FILES
[...]
          /usr[/local]/lib/gnupg/
                    Default location for extensions

Is it possible, to supply an option that sets the default
location for extensions, for example:

   gpg --extension-directory "$HOME"/lib/gnupg/

?  I know, that I can supply a default location during
./configure with the option --libdir="$HOME"/lib, but that
doesn't work, if my home directory gets moved after installing.