From: Pavel Sobolev <contact@paveloom.dev>
Subject: [PATCH] Use the system `discord-rpc` library.

Signed-off-by: Pavel Sobolev <contact@paveloom.dev>

--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -499,10 +499,7 @@ endif()
 
 # DiscordRPC
 if (USE_DISCORD_PRESENCE)
-    AddJsonPackage(discord-rpc)
-
-    target_include_directories(discord-rpc INTERFACE ${discord-rpc_SOURCE_DIR}/include)
-    add_library(DiscordRPC::discord-rpc ALIAS discord-rpc)
+    find_package(DiscordRPC REQUIRED)
 endif()
 
 # SimpleIni