Fixing CURLOPT_MAXAGE_CONN

It was not working at all before.
Better to get rid of TCP keepalive since it was not necessary.
Raising curl requirement level because of option.

Author: baranyaib90

README.md

@@ -43,7 +43,7 @@ only makes sense if you trust your DoH provider.
 
 ## Build
 
-Depends on `c-ares (>=1.11.0)`, `libcurl (>=7.64.0)`, `libev (>=4.25)`.
+Depends on `c-ares (>=1.11.0)`, `libcurl (>=7.65.0)`, `libev (>=4.25)`.
 
 On Debian-derived systems those are libc-ares-dev,
 libcurl4-{openssl,nss,gnutls}-dev and libev-dev respectively.

src/https_client.c

@@ -314,13 +314,8 @@ static void https_fetch_ctx_init(https_client_t *client,
   ASSERT_CURL_EASY_SETOPT(ctx, CURLOPT_POSTFIELDS, data);
   ASSERT_CURL_EASY_SETOPT(ctx, CURLOPT_WRITEFUNCTION, &write_buffer);
   ASSERT_CURL_EASY_SETOPT(ctx, CURLOPT_WRITEDATA, ctx);
-#ifdef CURLOPT_MAXAGE_CONN
-  ASSERT_CURL_EASY_SETOPT(ctx, CURLOPT_TCP_KEEPALIVE, 1L);
-  ASSERT_CURL_EASY_SETOPT(ctx, CURLOPT_TCP_KEEPIDLE, 50L);
-  ASSERT_CURL_EASY_SETOPT(ctx, CURLOPT_TCP_KEEPINTVL, 50L);
   ASSERT_CURL_EASY_SETOPT(ctx, CURLOPT_MAXAGE_CONN, 300L);
-#endif
-  // FIXME: consider adding usage of: CURLOPT_PIPEWAIT
+  // FIXME: consider adding CURLOPT_PIPEWAIT
   ASSERT_CURL_EASY_SETOPT(ctx, CURLOPT_USERAGENT, "https_dns_proxy/0.3");
   ASSERT_CURL_EASY_SETOPT(ctx, CURLOPT_FOLLOWLOCATION, 0);
   ASSERT_CURL_EASY_SETOPT(ctx, CURLOPT_NOSIGNAL, 0);