Commits
Benjamin Kietzman authored and Sutou Kouhei committed d542482bdc6
ARROW-7896: [C++] Refactor from #include guards to #pragma once Closes #6680 from bkietz/7896-Refactor-from-include-gua Authored-by: Benjamin Kietzman <bengilgit@gmail.com> Signed-off-by: Sutou Kouhei <kou@clear-code.com>