Update CMakeLists.txt

CMakeLists.txt

@@ -79,11 +79,23 @@ file(GLOB DETOURS_SRC_SHARED
 	detours/*.cpp
 )
 
+if(WIN32)
   file(GLOB OVERLAY_EXPERIMENTAL_SRC_SHARED
     overlay_experimental/*.cpp
+    overlay_experimental/windows/*.cpp
     ImGui/*.cpp
     ImGui/impls/*.cpp
+    ImGui/impls/windows/*.cpp
   )
+elseif(UNIX)
+  file(GLOB OVERLAY_EXPERIMENTAL_SRC_SHARED
+    overlay_experimental/*.cpp
+    overlay_experimental/linux/*.cpp
+    ImGui/*.cpp
+    ImGui/impls/*.cpp
+    ImGui/impls/linux/*.cpp
+  )
+endif()
 
 ###################################################
 # Setup for the steam_api(64).dll / libsteam_api.so