Don't use vendored dependencies in "dev-tools" (by default) if RTTR_U…

…SE_SYSTEM_LIBS is set

We should honor this variable also for the vendored dependencies in dev-tools

external/CMakeLists.txt

@@ -1,17 +1,18 @@
-# Copyright (C) 2005 - 2021 Settlers Freaks <sf-team at siedler25.org>
+# Copyright (C) 2005 - 2024 Settlers Freaks <sf-team at siedler25.org>
 #
 # SPDX-License-Identifier: GPL-2.0-or-later
 
 include(RttrTestingCfg)
 option(RTTR_EXTERNAL_BUILD_TESTING "Enable tests of external dependencies" OFF)
 set(BUILD_TESTING ${RTTR_EXTERNAL_BUILD_TESTING})
 
-if(EXISTS ${CMAKE_CURRENT_LIST_DIR}/dev-tools/CMakeLists.txt)
-    set(devToolsExist ON)
+if(NOT RTTR_USE_SYSTEM_LIBS AND EXISTS ${CMAKE_CURRENT_LIST_DIR}/dev-tools/CMakeLists.txt)
+    set(includeDevToolsDefault ON)
 else()
-    set(devToolsExist OFF)
+    set(includeDevToolsDefault OFF)
 endif()
-option(RTTR_INCLUDE_DEVTOOLS "Include folder with precompiled binaries for development" ${devToolsExist})
+
+option(RTTR_INCLUDE_DEVTOOLS "Include folder with precompiled binaries for development" ${includeDevToolsDefault})
 if(RTTR_INCLUDE_DEVTOOLS)
     add_subdirectory(dev-tools)
     set(CMAKE_PREFIX_PATH ${CMAKE_PREFIX_PATH} PARENT_SCOPE)