ldap: fix MinGW compiler warning

[MarcelRaad]

ldap_bind_s is marked as deprecated in w32api's winldap.h shipping with
the latest original MinGW, resulting in compiler warnings since commit
f0fe66f. Fix this for the non-SSPI
case by using ldap_simple_bind_s again instead of ldap_bind_s with
LDAP_AUTH_SIMPLE.

[mention-bot]

@MarcelRaad, thanks for your PR! By analyzing the history of the files in this pull request, we identified @captain-caveman2k, @bagder and @gknauf to be potential reviewers.

[coveralls]

Coverage increased (+0.08%) to 76.045% when pulling 3a1cde1 on MarcelRaad:ldap_mingw into a548183 on curl:master.

[snikulov]

@MarcelRaad It is not deprecated in Windows SDK https://msdn.microsoft.com/en-us/library/aa366156(v=vs.85).aspx.

So if you try to solve MinGW problem, could you please use #if defined(MINGW)... or something?

[MarcelRaad]

@snikulov Thanks for the comment! Yes, I have that problem only with MinGW (or, to be exact, with w32api, which is MinGW's version of the Windows SDK). But I don't understand what an #ifdef would gain us - do you think there is any downside of always using ldap_simple_bind_s instead of ldap_bind_s(..., LDAP_AUTH_SIMPLE) for simplicity?

(FWIW, ldap_bind_s seems to be deprecated in most implementations - OpenLDAP, IBM, Novell, Mozilla... - with recommendation to either use ldap_simple_bind_s or ldap_sasl_bind_s.)

[jay]

Both functions are documented for Vista+ but some searching just now shows them being used on earlier versions. Is one known to be more available than the other?

[snikulov]

@MarcelRaad @jay Changes looks good to me. ldap_simple_bind_s <=> ldap_bind_s + LDAP_AUTH_SIMPLE.
So go ahead and merge these changes.

[snikulov]

LGTM

[MarcelRaad]

ldap_simple_bind_s is available unconditionally in the Windows SDK that ships with Visual Studio 2005, which is the lowest version I have access to.

Thanks for the review!