Under Unix ‘gpgconf.ctl’ may be used to change some of the
compiled in directories where the GnuPG components are expected.  This
file is expected in the same directory as ‘gpgconf’.  The
physical installation directories are evaluated and no symlinks.
Blank lines and lines starting with pound sign are ignored in the
file.  The keywords must be followed by optional white space, an equal
sign, optional white space, and the value.  Environment variables are
substituted in standard shell manner, the final value must start with
a slash, trailing slashes are stripped.  Valid keywords are
rootdir, sysconfdir, socketdir, and
.enable.  No errors are printed for unknown keywords.  The
.enable keyword is special: if the keyword is used and its
value evaluates to true the entire file is ignored.

Under Windows this file is used to install GnuPG as a portable
application.  An empty file named ‘gpgconf.ctl’ is expected in
the same directory as the tool ‘gpgconf.exe’.  The root of the
installation is then that directory; or, if ‘gpgconf.exe’ has
been installed directly below a directory named ‘bin’, its parent
directory.  You also need to make sure that the following directories
exist and are writable: ‘ROOT/home’ for the GnuPG home and
‘ROOT/usr/local/var/cache/gnupg’ for internal cache files.