Before this patch, the result code was a mixture of `int` and
`CURLcode`.
Also adjust casts and fix a couple of minor issues found along the way.
Cherry-picked from #13489Closes#13600
- they are mostly pointless in all major jurisdictions
- many big corporations and projects already don't use them
- saves us from pointless churn
- git keeps history for us
- the year range is kept in COPYING
checksrc is updated to allow non-year using copyright statements
Closes#10205
1956 adds the sha256 value corresponding to an empty buffer
1957 adds an arbitrary value and confirms that the signature differs from 1956
1958 adds whitespace to 1957 and confirms that the signature matches 1957
1959 adds a value longer than 'char sha_hex[65]' in Curl_output_aws_sigv4()
Signed-off-by: Casey Bodley <cbodley@redhat.com>
Closes#9804
