[cmake] Can't use feature ldaps on Windows

[JackBoosY]

Hi guys:

Recently, we received an issue about curl (microsoft/vcpkg#14030), that reported that the feature ldaps could not be enabled on Windows.
Since curl in vcpkg uses cmake to build, I checked the cmake configuration in curl and found something strange:

curl/CMakeLists.txt

Lines 511 to 520 in abd846c

	if(NOT CURL_DISABLE_LDAP)
	if(WIN32)
	option(USE_WIN32_LDAP "Use Windows LDAP implementation" ON)
	if(USE_WIN32_LDAP)
	check_library_exists_concat("wldap32" cldap_open HAVE_WLDAP32)
	if(NOT HAVE_WLDAP32)
	set(USE_WIN32_LDAP OFF)
	endif()
	endif()
	endif()

Here we can use the system's ldaps on windows, but openldap is not disabled here, and:

curl/CMakeLists.txt

Lines 1398 to 1400 in abd846c

	_add_if("LDAPS" NOT CURL_DISABLE_LDAPS AND
	((USE_OPENLDAP AND SSL_ENABLED) OR
	(NOT USE_OPENLDAP AND HAVE_LDAP_SSL)))

There is no judgment variable USE_WIN32_LDAP when judging whether to enable ldaps.

I think that's caused this issue.
But even if I use USE_WIN32_LDAP and explicitly enable ldaps in the configuration log, using curl -V does not explicitly enable ldaps.
Configure log:

-- Enabled protocols: DICT FILE FTP FTPS GOPHER HTTP HTTPS IMAP IMAPS LDAP LDAPS MQTT POP3 POP3S RTSP SMB SMBS SMTP SMTPS TELNET TFTP

Result:

curl 7.73.0-DEV (Windows) libcurl/7.73.0-DEV Schannel zlib/1.2.11
Release-Date: [unreleased]
Protocols: dict file ftp ftps gopher http https imap imaps ldap mqtt pop3 pop3s rtsp smb smbs smtp smtps telnet tftp
Features: AsynchDNS IPv6 Kerberos Largefile NTLM SPNEGO SSL SSPI TrackMemory libz

I expected the following

ldaps should be enabled on Windows.

curl/libcurl version

7.73.0

[curl -V output]

curl 7.73.0-DEV (Windows) libcurl/7.73.0-DEV Schannel zlib/1.2.11
Release-Date: [unreleased]
Protocols: dict file ftp ftps gopher http https imap imaps ldap mqtt pop3 pop3s rtsp smb smbs smtp smtps telnet tftp
Features: AsynchDNS IPv6 Kerberos Largefile NTLM SPNEGO SSL SSPI TrackMemory libz

operating system

Windows 10, Visual Studio 2017, cmake 3.18.2

[bagder]

It seems nobody is going to work on this. I'll add it to KNOWN_BUGS.

[vszakats]

Proposing a fix for this in PR #10674.