general: conditionally compile gamemode on linux only

externals/CMakeLists.txt

@@ -189,7 +189,7 @@ if (ANDROID)
    endif()
 endif()
 
-if (UNIX)
+if (CMAKE_SYSTEM_NAME STREQUAL "Linux")
     add_subdirectory(gamemode)
 endif()
 

src/common/CMakeLists.txt

@@ -174,7 +174,7 @@ if(ANDROID)
     )
 endif()
 
-if (UNIX)
+if (CMAKE_SYSTEM_NAME STREQUAL "Linux")
   target_sources(common PRIVATE
     linux/gamemode.cpp
     linux/gamemode.h

src/common/linux/gamemode.cpp

@@ -4,6 +4,7 @@
 #include <gamemode_client.h>
 
 #include "common/linux/gamemode.h"
+#include "common/logging/log.h"
 #include "common/settings.h"
 
 namespace Common::Linux {