Enable linker optimizations in MSVC Release builds

Apparently /DEBUG implicitly disables linker optimizations. This
explicitly re-enables them, giving a 40% reduction in binary sizes and
a very slight runtime speed improvement.

CMakeLists.txt

@@ -48,7 +48,7 @@ else()
     set(CMAKE_CXX_FLAGS_RELEASE "${CMAKE_C_FLAGS_RELEASE}" CACHE STRING "" FORCE)
 
     set(CMAKE_EXE_LINKER_FLAGS_DEBUG   "/DEBUG" CACHE STRING "" FORCE)
-    set(CMAKE_EXE_LINKER_FLAGS_RELEASE "/DEBUG" CACHE STRING "" FORCE)
+    set(CMAKE_EXE_LINKER_FLAGS_RELEASE "/DEBUG /INCREMENTAL:NO /OPT:REF,ICF" CACHE STRING "" FORCE)
 endif()
 
 add_definitions(-DSINGLETHREADED)