discord: Add namespace and cleanup CMakeLists

CMakeLists.txt

@@ -212,6 +212,8 @@ find_package(GTest)
 
 pkg_check_modules(LIBSPARSEHASH IMPORTED_TARGET libsparsehash)
 
+find_package(RapidJSON)
+
 set(QT_VERSION_MAJOR 6)
 set(QT_MIN_VERSION 6.4.0)
 set(QT_DEFAULT_MAJOR_VERSION ${QT_VERSION_MAJOR})
@@ -364,7 +366,9 @@ optional_component(STREAMTAGREADER ON "Stream tagreader"
   DEPENDS "sparsehash" LIBSPARSEHASH_FOUND
 )
 
-optional_component(DISCORD_RPC ON "Discord Rich Presence")
+optional_component(DISCORD_RPC ON "Discord Rich Presence"
+  DEPENDS "RapidJSON" RapidJSON_FOUND
+)
 
 if(HAVE_SONGFINGERPRINTING OR HAVE_MUSICBRAINZ)
   set(HAVE_CHROMAPRINT ON)
@@ -1489,8 +1493,8 @@ if(LINUX AND LSB_RELEASE_EXEC AND DPKG_BUILDPACKAGE)
 endif()
 
 if(HAVE_DISCORD_RPC)
-  add_subdirectory(thirdparty/discord-rpc)
-  target_include_directories(strawberry_lib PUBLIC thirdparty/discord-rpc/include)
+  add_subdirectory(3rdparty/discord-rpc)
+  target_include_directories(strawberry_lib PUBLIC 3rdparty/discord-rpc/include)
 endif()
 
 if(HAVE_TRANSLATIONS)