MDEV-13836 mariadb_config & mysql_config output differ

compile C/C with system zlib, when the server uses system zlib

cmake/mariadb_connector_c.cmake

@@ -7,10 +7,8 @@ ENDIF()
 SET(CONC_WITH_SIGNCODE ${SIGNCODE})
 SET(SIGN_OPTIONS ${SIGNTOOL_PARAMETERS})
 
-IF(TARGET zlib)
-  GET_PROPERTY(ZLIB_LIBRARY_LOCATION TARGET zlib PROPERTY LOCATION)
-ELSE()
-  SET(ZLIB_LIBRARY_LOCATION ${ZLIB_LIBRARY})
+IF(NOT TARGET zlib)
+  SET(CONC_WITH_EXTERNAL_ZLIB ON)
 ENDIF()
 
 IF(SSL_DEFINES MATCHES "YASSL")