follow the "proper secure idiom" described in the CAVEATS section of printf(3). reminded by tb@ and millert@

This adds a new flag, `got commit -A', that allows to specify the commit author but retains the "committer" (which is obtained as usual via GOT_AUTHOR, got.conf or git config.) with lots of help from and ok stsp

This should fail without creating any tag. Before, ssh-keygen(1) would print an error to stderr, but got would create an unsigned tag. ok op@

This adds a new -s flag to 'got tag' that specifies the signer identity (for example, a key file) of the tagger. The tag object will include a signature that validates each of the tag object headers and the tag message. Verifying these signed tags requires maintaining an allowed signers file which maps signer identities (i.e. the email address of the tagger) to SSH public keys. See ssh-keygen(1) for more details of the allowed signers file. After creating this file and providing the path to it in got.conf(5) using the allowed_signers option, tags may be verified using with 'got tag -V tag_name'. The return code will be non-zero if a signature fails to verify. ok stsp@

ok tracey

ok op, tracey

ok stsp

Problem pointed out by naddy for FreeBSD -portable. Discussed with millert, thomas adam, and naddy.

This is still not thread-safe but at least avoids errors overwriting each other in single-threaded contexts.

got_error_fmt() could eventually replace got_error_path() which has already been used to construct errors with strings that are not actually paths... ok millert@

suggested by and ok millert

$> got rm a got: : No such file or directory becomes $> got rm a got: /path/to/a: No such file or directory

also add got_error_prefix_errno2 and got_error_prefix_errno3 which should hopefully all be merged into a single function with variadic args (but can't alloc mem)