Support building with SSPI support under Windows

Author: alcaeus

config.w32

@@ -70,7 +70,7 @@ function MONGODB_ADD_SOURCES(dir, file_list)
 }
 
 ARG_ENABLE("mongodb", "MongoDB support", "no");
-ARG_WITH("mongodb-sasl", "MongoDB: Build against Cyrus-SASL", "yes");
+ARG_WITH("mongodb-sasl", "MongoDB: Build with SASL (cyrus, sspi)", "yes");
 ARG_WITH("mongodb-client-side-encryption", "MongoDB: Enable client-side encryption", "yes");
 
 if (PHP_MONGODB != "no") {
@@ -232,15 +232,21 @@ if (PHP_MONGODB != "no") {
     WARNING("mongodb libopenssl support not enabled, libs not found");
   }
 
-  // TODO: Support building with native GSSAPI (SSPI) on Windows
   if (PHP_MONGODB_SASL != "no" &&
       CHECK_LIB("libsasl.lib", "mongodb", PHP_MONGODB) &&
       CHECK_HEADER_ADD_INCLUDE("sasl/sasl.h", "CFLAGS_MONGODB")) {
     mongoc_opts.MONGOC_ENABLE_SASL = 1;
-    mongoc_opts.MONGOC_ENABLE_SASL_CYRUS = 1;
 
-    // Referenced by _mongoc_cyrus_verifyfile_cb in mongoc-cyrus.c on Windows
-    ADD_FLAG("CFLAGS_MONGODB", "/D MONGOC_CYRUS_PLUGIN_PATH_PREFIX=NULL");
+    if (PHP_MONGODB_SASL == "yes" || PHP_MONGODB_SASL == "cyrus") {
+      mongoc_opts.MONGOC_ENABLE_SASL_CYRUS = 1;
+
+      // Referenced by _mongoc_cyrus_verifyfile_cb in mongoc-cyrus.c on Windows
+      ADD_FLAG("CFLAGS_MONGODB", "/D MONGOC_CYRUS_PLUGIN_PATH_PREFIX=NULL");
+    } else if (PHP_MONGODB_SASL == "sspi") {
+      mongoc_opts.MONGOC_ENABLE_SASL_SSPI = 1;
+    } else {
+      WARNING("mongodb sasl support not enabled, unknown value for PHP_MONGODB_SASL: " + PHP_MONGODB_SASL);
+    }
 
     if (CHECK_FUNC_IN_HEADER("sasl/sasl.h", "sasl_client_done")) {
       mongoc_opts.MONGOC_HAVE_SASL_CLIENT_DONE = 1;