Merge 10.2 into 10.3

CMakeLists.txt

 # Copyright (c) 2006, 2017, Oracle and/or its affiliates.
-# Copyright (c) 2008, 2020, MariaDB Corporation.
+# Copyright (c) 2008, 2021, MariaDB Corporation.
 # 
 # This program is free software; you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
@@ -127,7 +127,7 @@ ENDIF()
 # NUMA
 SET(WITH_NUMA "AUTO" CACHE STRING "Build with non-uniform memory access, allowing --innodb-numa-interleave. Options are ON|OFF|AUTO. ON = enabled (requires NUMA library), OFF = disabled, AUTO = enabled if NUMA library found.")
 
-SET(MYSQL_MAINTAINER_MODE "AUTO" CACHE STRING "MySQL maintainer-specific development environment. Options are: ON OFF AUTO.")
+SET(MYSQL_MAINTAINER_MODE "AUTO" CACHE STRING "Enable MariaDB maintainer-specific warnings. One of: NO (warnings are disabled) WARN (warnings are enabled) ERR (warnings are errors) AUTO (warnings are errors in Debug only)")
 
 # Packaging
 IF (NOT CPACK_GENERATOR)

cmake/maintainer.cmake

 # Copyright (c) 2010, 2014, Oracle and/or its affiliates. All rights reserved.
-# Copyright (c) 2020, MariaDB
+# Copyright (c) 2011, 2021, MariaDB
 #
 # This program is free software; you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
@@ -14,7 +14,7 @@
 # along with this program; if not, write to the Free Software
 # Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1335  USA
 
-IF(MSVC)
+IF(MYSQL_MAINTAINER_MODE STREQUAL "NO")
   RETURN()
 ENDIF()
 
@@ -46,7 +46,7 @@ IF(CMAKE_COMPILER_IS_GNUCC AND CMAKE_C_COMPILER_VERSION VERSION_LESS "6.0.0")
   SET(MY_ERROR_FLAGS ${MY_ERROR_FLAGS} -Wno-error=maybe-uninitialized)
 ENDIF()
 
-IF(MYSQL_MAINTAINER_MODE MATCHES "OFF")
+IF(MYSQL_MAINTAINER_MODE MATCHES "OFF|WARN")
   RETURN()
 ELSEIF(MYSQL_MAINTAINER_MODE MATCHES "AUTO")
   SET(WHERE DEBUG)