core, w32: Add w64 handling for regkeys
* src/w32-util.c (_gpgme_get_gpg_path): Use new defines. (GNUPG_REGKEY_2): x64 aware regkey as used by GnuPG in Gpg4win 2.x (GNUPG_REGKEY_3): x64 aware regkey as used by GnuPG in Gpg4win 3.x (_gpgme_get_gpgconf_path): Use new regkeys. Add another fallback.
This should fix more "unsupported protocol" issues if Gpg4win /
GnuPG is installed in a non standard path on 64bit systems.
The regkey handling is similar to that of gpgex and gpgol.
- GnuPG-Bug-Id: T3988