Fix warnings

This change fixes Cosmopolitan so it has fewer opinions about compiler
warnings. The whole repository had to be cleaned up to be buildable in
-Werror -Wall mode. This lets us benefit from things like strict const
checking. Some actual bugs might have been caught too.

third_party/tidy/language.c

@@ -408,7 +408,7 @@ Bool TY_(tidySetLanguage)( ctmbstr languageCode )
 
     if ( strlen( wantCode ) > 2 )
     {
-        strncpy(lang, wantCode, 2);
+        strncpy(__veil("r", lang), __veil("r", wantCode), __veil("r", 2));
         lang[2] = '\0';
         dict2 = TY_(tidyTestLanguage( lang ) ); /* BACKUP language? */
     }

third_party/tidy/parser.c

@@ -2796,6 +2796,7 @@ Node* TY_(ParseHTML)( TidyDocImpl *doc, Node *html, GetTokenMode mode )
     Node *frameset = NULL;
     Node *noframes = NULL;
     DEBUG_LOG_COUNTERS;
+    (void)head;
 
     enum parserState {
         STATE_INITIAL,                /* This is the initial state for every parser. */

third_party/tidy/tmbstr.c

@@ -266,7 +266,7 @@ void TY_(strrep)(tmbstr buffer, ctmbstr str, ctmbstr rep)
             }
             else
             {
-                strncpy(buf,buffer,strlen(buffer) - strlen(p));
+                strncpy(__veil("r", buf),__veil("r", buffer),__veil("r", strlen(buffer) - strlen(p)));
                 strcat(buf,rep);
                 strcat(buf,p+strlen(str));
             }