Rationale: Various compilation errors fixed as per https://aur.archlinux.org/cgit/aur.git/commit/?h=warmux&id=bb434ffa6c95496624d083fd32df87b03e78e8a4

diff -ru a/lib/warmux/net/download.cpp b/lib/warmux/net/download.cpp
--- a/lib/warmux/net/download.cpp	2016-08-05 11:57:19.524227773 +0300
+++ b/lib/warmux/net/download.cpp	2016-08-05 12:01:13.534472330 +0300
@@ -47,24 +47,24 @@
 #endif
 
   curl = curl_easy_init();
-  curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, download_callback);
+  curl_easy_setopt((CURL*)curl, CURLOPT_WRITEFUNCTION, download_callback);
   curl_error_buf = new char[CURL_ERROR_SIZE];
-  curl_easy_setopt(curl, CURLOPT_ERRORBUFFER, curl_error_buf);
-  curl_easy_setopt(curl, CURLOPT_FOLLOWLOCATION, 1);
+  curl_easy_setopt((CURL*)curl, CURLOPT_ERRORBUFFER, curl_error_buf);
+  curl_easy_setopt((CURL*)curl, CURLOPT_FOLLOWLOCATION, 1);
 }
 
 Downloader::~Downloader()
 {
-  curl_easy_cleanup(curl);
+  curl_easy_cleanup((CURL*)curl);
   curl_global_cleanup();
   delete[] curl_error_buf;
 }
 
 bool Downloader::Get(const char* url, FILE* file)
 {
-  curl_easy_setopt(curl, CURLOPT_FILE, file);
-  curl_easy_setopt(curl, CURLOPT_URL, url);
-  CURLcode r = curl_easy_perform(curl);
+  curl_easy_setopt((CURL*)curl, CURLOPT_FILE, file);
+  curl_easy_setopt((CURL*)curl, CURLOPT_URL, url);
+  CURLcode r = curl_easy_perform((CURL*)curl);
   fflush(file);
 
   if (r == CURLE_OK)