urldata: make service names unconditional

The ifdefs have become quite long. Also, the condition for the
definition of CURLOPT_SERVICE_NAME and for setting it from
CURLOPT_SERVICE_NAME have diverged. We will soon also need the two
options for NTLM, at least when using SSPI, for
https://github.com/curl/curl/pull/1660.
Just make the definitions unconditional to make that easier.

Closes https://github.com/curl/curl/pull/2479

lib/setopt.c

@@ -1039,6 +1039,7 @@ CURLcode Curl_vsetopt(struct Curl_easy *data, CURLoption option,
      */
     data->set.socks5_gssapi_nec = (0 != va_arg(param, long)) ? TRUE : FALSE;
     break;
+#endif
 
   case CURLOPT_SOCKS5_GSSAPI_SERVICE:
   case CURLOPT_PROXY_SERVICE_NAME:
@@ -1048,10 +1049,7 @@ CURLcode Curl_vsetopt(struct Curl_easy *data, CURLoption option,
     result = Curl_setstropt(&data->set.str[STRING_PROXY_SERVICE_NAME],
                             va_arg(param, char *));
     break;
-#endif
 
-#if !defined(CURL_DISABLE_CRYPTO_AUTH) || defined(USE_KERBEROS5) ||     \
-  defined(USE_SPNEGO)
   case CURLOPT_SERVICE_NAME:
     /*
      * Set authentication service name for DIGEST-MD5, Kerberos 5 and SPNEGO
@@ -1060,8 +1058,6 @@ CURLcode Curl_vsetopt(struct Curl_easy *data, CURLoption option,
                             va_arg(param, char *));
     break;
 
-#endif
-
   case CURLOPT_HEADERDATA:
     /*
      * Custom pointer to pass the header write callback function

lib/urldata.h

@@ -1422,13 +1422,8 @@ enum dupstring {
   STRING_SSH_HOST_PUBLIC_KEY_MD5, /* md5 of host public key in ascii hex */
   STRING_SSH_KNOWNHOSTS,  /* file name of knownhosts file */
 #endif
-#if defined(HAVE_GSSAPI) || defined(USE_WINDOWS_SSPI)
   STRING_PROXY_SERVICE_NAME, /* Proxy service name */
-#endif
-#if !defined(CURL_DISABLE_CRYPTO_AUTH) || defined(USE_KERBEROS5) || \
-  defined(USE_SPNEGO) || defined(HAVE_GSSAPI)
   STRING_SERVICE_NAME,    /* Service name */
-#endif
   STRING_MAIL_FROM,
   STRING_MAIL_AUTH,