CMake win32 fix (#837)

* use imgui_impl_win32 on windows

* make WICKED_LINUX_TEMPLATE a dependent option

Example_ImGui/CMakeLists.txt

@@ -18,8 +18,6 @@ set (SOURCE_FILES
 	ImGui/imstb_rectpack.h
 	ImGui/imstb_textedit.h
 	ImGui/imstb_truetype.h
-	ImGui/imgui_impl_sdl.cpp
-	ImGui/imgui_impl_sdl.h
 )
 
 if (WIN32)
@@ -27,6 +25,8 @@ if (WIN32)
 		main_Windows.cpp
 		main_Windows.h
 		Tests.rc
+		ImGui/imgui_impl_win32.cpp
+		ImGui/imgui_impl_win32.h
 	)
 
 	add_executable(Example_ImGui WIN32 ${SOURCE_FILES})
@@ -38,6 +38,8 @@ if (WIN32)
 else()
 	list (APPEND SOURCE_FILES
 		main_SDL2.cpp
+		ImGui/imgui_impl_sdl.cpp
+		ImGui/imgui_impl_sdl.h
 	)
 
 	add_executable(Example_ImGui ${SOURCE_FILES})