NTLM: is supported in GnuTLS builds too

... since commit 9a4c887c4a introduced in libcurl 7.19.4

docs/libcurl/curl_easy_setopt.3

@@ -1064,8 +1064,8 @@ HTTP NTLM authentication. A proprietary protocol invented and used by
 Microsoft. It uses a challenge-response and hash concept similar to Digest, to
 prevent the password from being eavesdropped.
 
-You need to build libcurl with either OpenSSL or NSS support for this option
-to work, or build libcurl on Windows.
+You need to build libcurl with either OpenSSL, GnuTLS or NSS support for this
+option to work, or build libcurl on Windows.
 .IP CURLAUTH_NTLM_WB
 NTLM delegating to winbind helper. Authentication is performed by a separate
 binary application that is executed when needed. The name of the application