trurl: disable URL encoding when setting a host to an IPv6 address

Fixes #279
Closes #280

Author: bagder

tests.json

@@ -2430,5 +2430,19 @@
               }
           ]
       }
+  },
+  {
+      "input": {
+          "arguments": [
+              "example.com",
+              "--set",
+              "host=[::1]"
+          ]
+      },
+      "expected": {
+          "stdout": "http://[::1]/\n",
+          "stderr": "",
+          "returncode": 0
+      }
   }
 ]

trurl.c

@@ -877,6 +877,9 @@ static const struct var *setone(CURLU *uh, const char *setline,
     v = comp2var(setline, vlen);
     if(v) {
       CURLUcode rc;
+      if((v->part == CURLUPART_HOST) && ('[' == ptr[1]))
+        /* when setting an IPv6 numerical address, disable URL encoding */
+        urlencode = false;
       rc = curl_url_set(uh, v->part, ptr[1] ? &ptr[1] : NULL,
                         (o->curl ? 0 : CURLU_NON_SUPPORT_SCHEME)|
                         (urlencode ? CURLU_URLENCODE : 0) );