Option flags for git_repository_open_ext.

• GIT_REPOSITORY_OPEN_NO_SEARCH - Only open the repository if it can be immediately found in the start_path. Do not walk up from the start_path looking at parent directories.
• GIT_REPOSITORY_OPEN_CROSS_FS - Unless this flag is set, open will not continue searching across filesystem boundaries (i.e. when st_dev changes from the stat system call). (E.g. Searching in a user's home directory "/home/user/source/" will not return "/.git/" as the found repo if "/" is a different filesystem than "/home".)
• GIT_REPOSITORY_OPEN_BARE - Open repository as a bare repo regardless of core.bare config, and defer loading config file for faster setup. Unlike git_repository_open_bare, this can follow gitlinks.