according to https://curl.se/libcurl/c/curl_easy_setopt.html, parameters
are either a long, a function pointer, an object pointer or a curl_off_t,
depending on what the option expects; curl 8.16 checks and warns about
these.
* check_curl: avoid freeing memory when we don't know where it came from
* check_curl: when using -f sticky conserve IPv6 addresses properly
When running the check on an ipv6 address with a sticky onredirect
policy like in this example:
check_curl -6 -H example.com -I ::1 -f sticky
It results in a getaddrinfo error:
HTTP CRITICAL - Unable to lookup IP address for '[::1]': getaddrinfo returned -3 - Temporary failure in name resolution
This happens because in check_http() if the content of server_addr is an
ipv6 address enclosing brackets are added and on redirection a
subsequent call to check_http() will pass this now bracketed value to
getaddrinfo resulting in the error.
To work around this, strip the brackets from the address prior to the
lookup_host() call.
* add Michael Jeanson to thanks
If the status line from a server ended with '\n' instead
of '\r\n' (defined by RFC 9112), check_curl failed to parse it
and exited with an alarm.
The RFC recommends to be lenient here and this change follows that
suggestion.
