ARROW-18260: [C++][CMake] Add support for x64 for CMAKE_SYSTEM_PROCESSOR (#14598)
ARROW-18260: [C++][CMake] Add support for x64 for CMAKE_SYSTEM_PROCESSOR (#14598)

vcpkg uses x64:

https://vcpkg.readthedocs.io/en/latest/users/triplets/

> Valid options are x86, x64, arm, arm64 and wasm32.

Authored-by: Sutou Kouhei <73218711cdd5d5c30ac66da3cc4d9d9204caf34b@clear-code.com>
Signed-off-by: Sutou Kouhei <73218711cdd5d5c30ac66da3cc4d9d9204caf34b@clear-code.com>
kou/arrow,kou/arrow,kou/arrow,apache/arrow,apache/arrow,kou/arrow,kou/arrow,apache/arrow,kou/arrow,apache/arrow,kou/arrow,apache/arrow,apache/arrow,apache/arrow,apache/arrow,kou/arrow,apache/arrow,kou/arrow,apache/arrow,apache/arrow,kou/arrow,kou/arrow,apache/arrow,apache/arrow,kou/arrow,kou/arrow,apache/arrow,kou/arrow