urldata: convert bools to bitfields and move to end

This allows the compiler to pack and align the structs better in
memory. For a rather feature-complete build on x86_64 Linux, gcc 8.1.2
makes the Curl_easy struct 4.9% smaller. From 6312 bytes to 6000.

Removed an unused struct field.

No functionality changes.

Closes #3610

lib/connect.c

@@ -1434,7 +1434,7 @@ void Curl_conncontrol(struct connectdata *conn,
   if((ctrl == CONNCTRL_STREAM) &&
      (conn->handler->flags & PROTOPT_STREAM))
     DEBUGF(infof(conn->data, "Kill stream: %s\n", reason));
-  else if(closeit != conn->bits.close) {
+  else if((bit)closeit != conn->bits.close) {
     DEBUGF(infof(conn->data, "Marked for [%s]: %s\n",
                  closeit?"closure":"keep alive", reason));
     conn->bits.close = closeit; /* the only place in the source code that

lib/ftp.c

@@ -4395,7 +4395,6 @@ static CURLcode ftp_setup_connection(struct connectdata *conn)
     return CURLE_OUT_OF_MEMORY;
 
   ftp->path = &data->state.up.path[1]; /* don't include the initial slash */
-  data->state.slash_removed = TRUE; /* we've skipped the slash */
 
   /* FTP URLs support an extension like ";type=<typecode>" that
    * we'll try to get now! */

lib/http.c

@@ -751,7 +751,7 @@ Curl_http_output_auth(struct connectdata *conn,
 #ifndef CURL_DISABLE_PROXY
   /* Send proxy authentication header if needed */
   if(conn->bits.httpproxy &&
-      (conn->bits.tunnel_proxy == proxytunnel)) {
+     (conn->bits.tunnel_proxy == (bit)proxytunnel)) {
     result = output_auth_headers(conn, authproxy, request, path, TRUE);
     if(result)
       return result;

lib/setopt.c

@@ -682,7 +682,7 @@ static CURLcode vsetopt(struct Curl_easy *data, CURLoption option,
      * Set header option.
      */
     arg = va_arg(param, long);
-    data->set.sep_headers = (arg & CURLHEADER_SEPARATE)? TRUE: FALSE;
+    data->set.sep_headers = (bool)((arg & CURLHEADER_SEPARATE)? TRUE: FALSE);
     break;
 
   case CURLOPT_HTTP200ALIASES:
@@ -884,7 +884,8 @@ static CURLcode vsetopt(struct Curl_easy *data, CURLoption option,
 
     /* the DIGEST_IE bit is only used to set a special marker, for all the
        rest we need to handle it as normal DIGEST */
-    data->state.authhost.iestyle = (auth & CURLAUTH_DIGEST_IE) ? TRUE : FALSE;
+    data->state.authhost.iestyle =
+      (bool)((auth & CURLAUTH_DIGEST_IE) ? TRUE : FALSE);
 
     if(auth & CURLAUTH_DIGEST_IE) {
       auth |= CURLAUTH_DIGEST; /* set standard digest bit */
@@ -967,7 +968,8 @@ static CURLcode vsetopt(struct Curl_easy *data, CURLoption option,
 
     /* the DIGEST_IE bit is only used to set a special marker, for all the
        rest we need to handle it as normal DIGEST */
-    data->state.authproxy.iestyle = (auth & CURLAUTH_DIGEST_IE) ? TRUE : FALSE;
+    data->state.authproxy.iestyle =
+      (bool)((auth & CURLAUTH_DIGEST_IE) ? TRUE : FALSE);
 
     if(auth & CURLAUTH_DIGEST_IE) {
       auth |= CURLAUTH_DIGEST; /* set standard digest bit */
@@ -2076,13 +2078,15 @@ static CURLcode vsetopt(struct Curl_easy *data, CURLoption option,
 
   case CURLOPT_SSL_OPTIONS:
     arg = va_arg(param, long);
-    data->set.ssl.enable_beast = arg&CURLSSLOPT_ALLOW_BEAST?TRUE:FALSE;
+    data->set.ssl.enable_beast =
+      (bool)((arg&CURLSSLOPT_ALLOW_BEAST) ? TRUE : FALSE);
     data->set.ssl.no_revoke = !!(arg & CURLSSLOPT_NO_REVOKE);
     break;
 
   case CURLOPT_PROXY_SSL_OPTIONS:
     arg = va_arg(param, long);
-    data->set.proxy_ssl.enable_beast = arg&CURLSSLOPT_ALLOW_BEAST?TRUE:FALSE;
+    data->set.proxy_ssl.enable_beast =
+      (bool)((arg&CURLSSLOPT_ALLOW_BEAST) ? TRUE : FALSE);
     data->set.proxy_ssl.no_revoke = !!(arg & CURLSSLOPT_NO_REVOKE);
     break;