This is a major lift into C++.

Much of the code is now building in C++, and I'm using C++23.

A spot test seems to work.  Now I can start to debride all the
painful memory management quirks...

src/auth.hh

@@ -0,0 +1,30 @@
+#pragma once
+
+#include "url.hh"
+
+enum AuthParseHTTPAuthType_t { TYPENOTSET, BASIC, DIGEST };
+enum AuthParseDigestAlgorithm_t { ALGORITHMNOTSET, MD5, MD5SESS };
+enum AuthParseDigestQOP_t { QOPNOTSET, AUTH, AUTHINT };
+
+typedef struct {
+   enum AuthParseHTTPAuthType_t type;
+   char *name;
+   Dlist *paths; /* stripped of any trailing '/', so the root path is "" */
+   char *authorization; /* BASIC: the authorization request header */
+                        /* DIGEST: the hexdigest of A1             */
+   /* digest state ahead */
+   char *username;
+   char *cnonce;
+   unsigned int nonce_count;
+   char *nonce;
+   char *opaque;
+   enum AuthParseDigestAlgorithm_t algorithm;
+   char *domain; /* NOT USED */
+   enum AuthParseDigestQOP_t qop;
+} AuthRealm_t;
+
+
+char *a_Auth_get_auth_str(const DilloUrl *url, const char *request_uri);
+int a_Auth_do_auth(Dlist *auth_string, const DilloUrl *url);
+void a_Auth_init(void);
+