set CURLOPT_ENCODING to nullptr in case of curl7 (#2737)

* set CURLOPT_ENCODING to nullptr in case of curl7

Curl 7 introduced more strictness how it handles CURLOPT_ENCODING.

With earlier versions it as apparently okay when the server sent an encoding curl did not implement.

Newer versions are much more stricter and refuse to complete downloads under such circumstances. This leads to almost nothing loading.
The culrpit seemingly being either the simulator or asset servers sending headers curls does not accept.

The workaround is to set CURLOPT_ENCODING to nullptr rather than "". This does come with the implication that curl will not handle decompression transparently, rather this burden gets shifted to the application.
It will also not send Accept-Encoding headers automatically.

* Adapt a few more occurences of CURLOPT_ENCODING for curl >= 7

Author: Nicky-D

indra/llcorehttp/_httpoprequest.cpp

@@ -513,7 +513,12 @@ HttpStatus HttpOpRequest::prepareRequest(HttpService * service)
     check_curl_easy_setopt(mCurlHandle, CURLOPT_NOPROGRESS, 1);
     check_curl_easy_setopt(mCurlHandle, CURLOPT_URL, mReqURL.c_str());
     check_curl_easy_setopt(mCurlHandle, CURLOPT_PRIVATE, getHandle());
-    check_curl_easy_setopt(mCurlHandle, CURLOPT_ENCODING, "");
+
+#if LIBCURL_VERSION_MAJOR > 7
+    check_curl_easy_setopt(mCurlHandle, CURLOPT_ENCODING, nullptr);
+#else
+     check_curl_easy_setopt(mCurlHandle, CURLOPT_ENCODING, "");
+#endif
 
     check_curl_easy_setopt(mCurlHandle, CURLOPT_AUTOREFERER, 1);
     check_curl_easy_setopt(mCurlHandle, CURLOPT_MAXREDIRS, HTTP_REDIRECTS_DEFAULT);
@@ -603,7 +608,12 @@ HttpStatus HttpOpRequest::prepareRequest(HttpService * service)
     case HOR_POST:
         {
             check_curl_easy_setopt(mCurlHandle, CURLOPT_POST, 1);
+
+#if LIBCURL_VERSION_MAJOR > 7
+            check_curl_easy_setopt(mCurlHandle, CURLOPT_ENCODING, nullptr);
+#else
             check_curl_easy_setopt(mCurlHandle, CURLOPT_ENCODING, "");
+#endif
             long data_size(0);
             if (mReqBody)
             {

indra/llcorehttp/httpcommon.cpp

@@ -289,7 +289,13 @@ CURL *getCurlTemplateHandle()
             check_curl_code(result, CURLOPT_NOSIGNAL);
             result = curl_easy_setopt(curlpTemplateHandle, CURLOPT_NOPROGRESS, 1);
             check_curl_code(result, CURLOPT_NOPROGRESS);
+
+#if LIBCURL_VERSION_MAJOR > 7
+            result = curl_easy_setopt(curlpTemplateHandle, CURLOPT_ENCODING, nullptr);
+#else
             result = curl_easy_setopt(curlpTemplateHandle, CURLOPT_ENCODING, "");
+#endif
+
             check_curl_code(result, CURLOPT_ENCODING);
             result = curl_easy_setopt(curlpTemplateHandle, CURLOPT_AUTOREFERER, 1);
             check_curl_code(result, CURLOPT_AUTOREFERER);