w32: Improve locating gpgconf on 64 bit systems.
w32: Improve locating gpgconf on 64 bit systems.

* src/w32-util.c (find_program_at_standard_place): Fallback to
CSIDL_PROGRAM_FILESX86.

Signed-off-by: Werner Koch <13bd1fc5137f503b0a8355ad400e7a87ebb45b25@gnupg.org>

gpg/gpgme,gpg/gpgme,gpg/gpgme,gpg/gpgme,gpg/gpgme,gpg/gpgme,gpg/gpgme