msvc: add VS2012 CI job, fix compiler warnings in LDAP and tests

Follow-up to 8cfc936f5c #10674
Follow-up to d620ec6791 #14700

Closes #15926

appveyor.yml

@@ -61,6 +61,16 @@ environment:
       ENABLE_UNICODE: 'OFF'
       SHARED: 'ON'
       EXAMPLES: 'ON'
+    - job_name: 'CMake, VS2012, Debug, x64, OpenSSL 1.1.1, Build-only'
+      APPVEYOR_BUILD_WORKER_IMAGE: 'Visual Studio 2015'
+      BUILD_SYSTEM: CMake
+      PRJ_GEN: 'Visual Studio 11 2012'
+      TARGET: '-A x64'
+      PRJ_CFG: Debug
+      OPENSSL: 'ON'
+      SCHANNEL: 'OFF'
+      ENABLE_UNICODE: 'OFF'
+      SHARED: 'ON'
     - job_name: 'CMake, VS2013, Debug, x64, OpenSSL 1.1.1, Build-only'
       APPVEYOR_BUILD_WORKER_IMAGE: 'Visual Studio 2015'
       BUILD_SYSTEM: CMake

lib/ldap.c

@@ -153,7 +153,7 @@ static void _ldap_free_urldesc(LDAPURLDesc *ludp);
 #define ldap_err2string ldap_err2stringA
 #endif
 
-#if defined(USE_WIN32_LDAP) && defined(_MSC_VER) && (_MSC_VER <= 1600)
+#if defined(USE_WIN32_LDAP) && defined(_MSC_VER) && (_MSC_VER <= 1700)
 /* Workaround for warning:
    'type cast' : conversion from 'int' to 'void *' of greater size */
 #undef LDAP_OPT_ON

tests/server/util.c

@@ -470,7 +470,7 @@ long timediff(struct timeval newer, struct timeval older)
 
 typedef void (*SIGHANDLER_T)(int);
 
-#if defined(_MSC_VER) && _MSC_VER == 1600
+#if defined(_MSC_VER) && (_MSC_VER <= 1700)
 /* Workaround for warning C4306:
    'type cast' : conversion from 'int' to 'void (__cdecl *)(int)' */
 #undef SIG_ERR