[lldb] Never compile the debugserver with Clang module flags

[teemperor]

Summary

Compiling ObjC++ with Clang modules is usually not working well and compiling
the small debugserver with modules is not worth the trouble.

[teemperor]

• rebased on top of D75164

lldb/tools/debugserver/CMakeLists.txt

 cmake_minimum_required(VERSION 3.4.3)
 
 project(Debugserver LANGUAGES C CXX ASM-ATT)
 
 if (CMAKE_SOURCE_DIR STREQUAL CMAKE_CURRENT_SOURCE_DIR)
   set(CMAKE_MODULE_PATH
     ${CMAKE_MODULE_PATH}
     "${CMAKE_SOURCE_DIR}/../../cmake"
     "${CMAKE_SOURCE_DIR}/../../cmake/modules"
     )
 
   include(LLDBStandalone)
   include(debugserverConfig)
   include(AddLLDB)
 
+  # debugserver contains ObjC++ code, so let's disable Clang modules
+  # in this subdirectory to avoid building ObjC++ modules (which often
+  # doesn't properly work).
+  remove_module_flags()
+
   set(LLDB_SOURCE_DIR "${CMAKE_SOURCE_DIR}/../../")
   include_directories(${LLDB_SOURCE_DIR}/include)
 endif()
 
 add_subdirectory(source)