netxlite: call getaddrinfo and handle platform-specific oddities (#764)

This commit changes our system resolver to call getaddrinfo directly when CGO is enabled. This change allows us to:

1. obtain the CNAME easily

2. obtain the real getaddrinfo retval

3. handle platform specific oddities such as `EAI_NODATA`
returned on Android devices

See https://github.com/ooni/probe/issues/2029 and https://github.com/ooni/probe/issues/2029#issuecomment-1140258729 in particular.

See https://github.com/ooni/probe/issues/2033 for documentation regarding the desire to see `getaddrinfo`'s retval.

See https://github.com/ooni/probe/issues/2118 for possible follow-up changes.

internal/netxlite/internal/generrno/main.go

@@ -149,6 +149,7 @@ var Specs = []*ErrorSpec{
 	NewWindowsError("NO_DATA", "DNS_no_answer"),                   // [ ] WSANO_DATA
 	NewWindowsError("NO_RECOVERY", "DNS_non_recoverable_failure"), // [*] WSANO_RECOVERY
 	NewWindowsError("TRY_AGAIN", "DNS_temporary_failure"),         // [*] WSATRY_AGAIN
+	NewWindowsError("HOST_NOT_FOUND", "DNS_NXDOMAIN_error"),       // [*] WSAHOST_NOT_FOUND
 
 	// Implementation note: we need to specify acronyms we
 	// want to be upper case in uppercase here. For example,
@@ -169,6 +170,10 @@ var Specs = []*ErrorSpec{
 	NewLibraryError("SSL_invalid_certificate"),
 	NewLibraryError("JSON_parse_error"),
 	NewLibraryError("connection_already_closed"),
+
+	// QUIRKS: the following errors exist to clearly flag strange
+	// underlying behavior implemented by platforms.
+	NewLibraryError("Android_DNS_cache_no_data"),
 }
 
 // mapSystemToLibrary maps the operating system name to the name