Add MariaDB Connector/C as a built-in alternative (v3.2.3).

vendor/MDBC/plugins/io/CMakeLists.txt

@@ -0,0 +1,15 @@
+IF (WITH_CURL)
+  INCLUDE(FindCURL)
+  IF(CURL_FOUND)
+
+    ADD_DEFINITIONS(-DHAVE_REMOTEIO=1)
+    #remote io plugin
+    REGISTER_PLUGIN(TARGET remote_io
+                  TYPE MARIADB_CLIENT_PLUGIN_IO
+                  CONFIGURATIONS DYNAMIC STATIC OFF
+                  DEFAULT DYNAMIC
+                  SOURCES ${CC_SOURCE_DIR}/plugins/io/remote_io.c
+                  INCLUDES ${CURL_INCLUDE_DIR}
+                  LIBRARIES ${CURL_LIBRARIES})
+  ENDIF()
+ENDIF()