git_signature_new() and git_signature_now() currently don't return error
codes. Change the API to return error codes and not pointers to let the
user handle errors properly.
Signed-off-by: schu <schu-github@schulog.org>
Most tags will have a timestamp of whenever the code is running and
dealing with time and timezones is error-prone. Optimize for this case
by adding a function which causes the signature to be created with a
current timestamp.
Signed-off-by: Carlos Martín Nieto <cmn@elego.de>
