cmake: move gamemode target include into its file

externals/CMakeLists.txt

@@ -191,7 +191,6 @@ endif()
 
 if (UNIX)
     add_subdirectory(gamemode)
-    target_include_directories(gamemode PUBLIC gamemode/include)
 endif()
 
 # Breakpad

externals/gamemode/CMakeLists.txt

@@ -1,7 +1,7 @@
 # SPDX-FileCopyrightText: Copyright 2023 yuzu Emulator Project
 # SPDX-License-Identifier: GPL-3.0-or-later
 
-project(gamemode)
+project(gamemode LANGUAGES CXX C)
 
 add_library(gamemode include/gamemode_client.h)
 

src/yuzu_cmd/CMakeLists.txt

@@ -44,7 +44,6 @@ target_link_libraries(yuzu-cmd PRIVATE SDL2::SDL2 Vulkan::Headers)
 
 if(UNIX AND NOT APPLE)
     install(TARGETS yuzu-cmd)
-    target_link_libraries(yuzu-cmd PRIVATE gamemode)
 endif()
 
 if(WIN32)