diff --git a/CMakeLists.txt b/CMakeLists.txt
index 091b25c0..b654112e 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -138,6 +138,11 @@ if (APPLE AND USE_TLS AND NOT USE_MBED_TLS)
   target_link_libraries(ixwebsocket "-framework foundation" "-framework security")
 endif()
 
+if (WIN32)
+  target_link_libraries(ixwebsocket wsock32 ws2_32)
+  add_definitions(-D_CRT_SECURE_NO_WARNINGS)
+endif()
+
 if (UNIX)
   find_package(Threads)
   target_link_libraries(ixwebsocket ${CMAKE_THREAD_LIBS_INIT})
@@ -165,15 +170,14 @@ if (USE_TLS AND USE_MBED_TLS)
   endif()
 endif()
 
-find_package(ZLIB REQUIRED)
+find_package(ZLIB)
 if (ZLIB_FOUND)
   include_directories(${ZLIB_INCLUDE_DIRS})
   target_link_libraries(ixwebsocket ${ZLIB_LIBRARIES})
 else()
   add_subdirectory(third_party/zlib)
   include_directories(third_party/zlib ${CMAKE_CURRENT_BINARY_DIR}/third_party/zlib)
-  target_link_libraries(ixwebsocket zlibstatic wsock32 ws2_32)
-  add_definitions(-D_CRT_SECURE_NO_WARNINGS)
+  target_link_libraries(ixwebsocket zlibstatic)
 endif()
 
 set( IXWEBSOCKET_INCLUDE_DIRS