MDEV-8969 groonga is compiled even with -DPLUGIN_MROONGA=NO

first add mroonga plugin (MYSQL_ADD_PLUGIN) then add dependent
targets (add_subdirectory(groonga))

storage/mroonga/CMakeLists.txt

@@ -51,12 +51,6 @@ if(MSVC)
   endif()
 endif()
 
-if(MRN_BUNDLED)
-  if(WITHOUT_MROONGA OR WITHOUT_MROONGA_STORAGE_ENGINE)
-    return()
-  endif()
-endif()
-
 set(MRN_BUNDLED_GROONGA_RELATIVE_DIR "vendor/groonga")
 set(MRN_BUNDLED_GROONGA_DIR
   "${CMAKE_CURRENT_SOURCE_DIR}/${MRN_BUNDLED_GROONGA_RELATIVE_DIR}")
@@ -85,44 +79,6 @@ file(READ ${MRN_SOURCE_DIR}/version_micro  MRN_VERSION_MICRO)
 file(READ ${MRN_SOURCE_DIR}/version_in_hex MRN_VERSION_IN_HEX)
 file(READ ${MRN_SOURCE_DIR}/plugin_version MRN_PLUGIN_VERSION)
 
-if(MRN_GROONGA_BUNDLED)
-  option(MRN_GROONGA_EMBED
-    "Embed libgroonga"
-    ON)
-  if(MRN_GROONGA_EMBED)
-    set(GRN_EMBED ON)
-  endif()
-
-  set(MRN_BUNDLED_GROONGA_NORMALIZER_MYSQL_DIR
-    "${MRN_BUNDLED_GROONGA_DIR}/vendor/plugins/groonga-normalizer-mysql")
-  option(MRN_GROONGA_NORMALIZER_MYSQL_EMBED
-    "Embed groonga-normalizer-mysql Groonga plugin"
-    ON)
-  if(EXISTS ${MRN_BUNDLED_GROONGA_NORMALIZER_MYSQL_DIR})
-    set(GROONGA_NORMALIZER_MYSQL_FOUND ON)
-  else()
-    set(GROONGA_NORMALIZER_MYSQL_FOUND OFF)
-    set(MRN_GROONGA_NORMALIZER_MYSQL_EMBED OFF)
-  endif()
-  if(MRN_GROONGA_NORMALIZER_MYSQL_EMBED)
-    set(GROONGA_NORMALIZER_MYSQL_EMBED ON)
-  endif()
-
-  add_subdirectory("${MRN_BUNDLED_GROONGA_RELATIVE_DIR}")
-else()
-  set(MRN_GROONGA_EMBED OFF)
-
-  file(READ ${MRN_SOURCE_DIR}/required_groonga_version REQUIRED_GROONGA_VERSION)
-  string(STRIP "${REQUIRED_GROONGA_VERSION}" REQUIRED_GROONGA_VERSION)
-
-  file(READ
-    ${MRN_SOURCE_DIR}/required_groonga_normalizer_mysql_version
-    REQUIRED_GROONGA_NORMALIZER_MYSQL_VERSION)
-  string(STRIP
-    "${REQUIRED_GROONGA_NORMALIZER_MYSQL_VERSION}"
-    REQUIRED_GROONGA_NORMALIZER_MYSQL_VERSION)
-endif()
-
 set(MRN_PACKAGE_STRING "${PROJECT_NAME} ${MRN_VERSION}")
 
 include(CheckCCompilerFlag)
@@ -151,7 +107,18 @@ read_file_list(${CMAKE_CURRENT_SOURCE_DIR}/udf/sources.am MRN_UDF_SOURCES)
 string(REGEX REPLACE "([^;]+)" "${MRN_RELATIVE_DIR_PREFIX}udf/\\1"
   MRN_UDF_SOURCES "${MRN_UDF_SOURCES}")
 
+set(MRN_ALL_SOURCES
+  ${MRN_SOURCES}
+  ${MRN_UDF_SOURCES}
+  ${LIBMRN_NO_MYSQL_SOURCES}
+  ${LIBMRN_NEED_MYSQL_SOURCES})
+
 if(MRN_BUNDLED)
+  mysql_add_plugin(mroonga ${MRN_ALL_SOURCES} STORAGE_ENGINE MODULE_ONLY)
+  if(NOT TARGET mroonga)
+    return()
+  endif()
+
   set(MYSQL_SOURCE_DIR ${CMAKE_SOURCE_DIR})
   set(MYSQL_BUILD_DIR ${MYSQL_SOURCE_DIR})
   set(MYSQL_CONFIG ${CMAKE_SOURCE_DIR}/scripts/mysql_config)
@@ -167,6 +134,44 @@ else()
 endif()
 find_path(MYSQL_CONFIG "${MYSQL_CONFIG}")
 
+if(MRN_GROONGA_BUNDLED)
+  option(MRN_GROONGA_EMBED
+    "Embed libgroonga"
+    ON)
+  if(MRN_GROONGA_EMBED)
+    set(GRN_EMBED ON)
+  endif()
+
+  set(MRN_BUNDLED_GROONGA_NORMALIZER_MYSQL_DIR
+    "${MRN_BUNDLED_GROONGA_DIR}/vendor/plugins/groonga-normalizer-mysql")
+  option(MRN_GROONGA_NORMALIZER_MYSQL_EMBED
+    "Embed groonga-normalizer-mysql Groonga plugin"
+    ON)
+  if(EXISTS ${MRN_BUNDLED_GROONGA_NORMALIZER_MYSQL_DIR})
+    set(GROONGA_NORMALIZER_MYSQL_FOUND ON)
+  else()
+    set(GROONGA_NORMALIZER_MYSQL_FOUND OFF)
+    set(MRN_GROONGA_NORMALIZER_MYSQL_EMBED OFF)
+  endif()
+  if(MRN_GROONGA_NORMALIZER_MYSQL_EMBED)
+    set(GROONGA_NORMALIZER_MYSQL_EMBED ON)
+  endif()
+
+  add_subdirectory("${MRN_BUNDLED_GROONGA_RELATIVE_DIR}")
+else()
+  set(MRN_GROONGA_EMBED OFF)
+
+  file(READ ${MRN_SOURCE_DIR}/required_groonga_version REQUIRED_GROONGA_VERSION)
+  string(STRIP "${REQUIRED_GROONGA_VERSION}" REQUIRED_GROONGA_VERSION)
+
+  file(READ
+    ${MRN_SOURCE_DIR}/required_groonga_normalizer_mysql_version
+    REQUIRED_GROONGA_NORMALIZER_MYSQL_VERSION)
+  string(STRIP
+    "${REQUIRED_GROONGA_NORMALIZER_MYSQL_VERSION}"
+    REQUIRED_GROONGA_NORMALIZER_MYSQL_VERSION)
+endif()
+
 if(EXISTS "${MYSQL_SOURCE_DIR}/storage/maria")
   set(MYSQL_VARIANT "MariaDB")
 else()
@@ -286,17 +291,8 @@ link_directories(
   ${MRN_LIBRARY_DIRS}
   ${MYSQL_LIBRARY_DIRS})
 
-set(MRN_ALL_SOURCES
-  ${MRN_SOURCES}
-  ${MRN_UDF_SOURCES}
-  ${LIBMRN_NO_MYSQL_SOURCES}
-  ${LIBMRN_NEED_MYSQL_SOURCES})
-
 if(MRN_BUNDLED)
-  mysql_add_plugin(mroonga
-    ${MRN_ALL_SOURCES}
-    STORAGE_ENGINE MODULE_ONLY
-    LINK_LIBRARIES ${MRN_LIBRARIES})
+  target_link_libraries(mroonga ${MRN_LIBRARIES})
 else()
   add_library(mroonga MODULE ${MRN_ALL_SOURCES})