Loop over all the git attributes for a path.
A combination of GIT_ATTR_CHECK... flags.
Path inside the repo to check attributes. This does not have to exist, but if it does not, then it will be treated as a plain file (i.e. not a directory).
Function to invoke on each attribute name and value. The value may be NULL is the attribute is explicitly set to UNSPECIFIED using the '!' sign. Callback will be invoked only once per attribute name, even if there are multiple rules for a given file. The highest priority rule will be used. Return a non-zero value from this to stop looping.
Passed on as extra parameter to callback function.
0 on success, GIT_EUSER on non-zero callback, or error code