diff --git a/CMakeLists.txt b/CMakeLists.txt
index 1170c79..9c549bf 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -28,11 +28,17 @@ if(DEFINED IOS_ISH)
 message(STATUS "INPUT IOS_ISH ${IOS_ISH}")
 endif()
 
-if(DEFINED XP_SYSTEM)
-message(STATUS "transm use xp defined ${XP_SYSTEM}")
-add_definitions(-D_WIN32_WINNT=0x0501)
+if(WIN32)
+execute_process(COMMAND cmd /c ver
+    OUTPUT_VARIABLE VER_OUTPUT
+    OUTPUT_STRIP_TRAILING_WHITESPACE)
+if(VER_OUTPUT MATCHES "XP")
+    message(STATUS "Windows XP platform.")
+    add_definitions(-D_WIN32_WINNT=0x0501)
 else()
-add_definitions(-D_WIN32_WINNT=0x0601)
+    message(STATUS "Windows NT platform.")
+    add_definitions(-D_WIN32_WINNT=0x0601)
+endif()
 endif()
 
 set(CMAKE_DEBUG_POSTFIX "d")
@@ -65,19 +71,6 @@ else()
 add_subdirectory(http-server)
 endif()
 
-if(WIN32)
-execute_process(COMMAND cmd /c ver
-    OUTPUT_VARIABLE VER_OUTPUT
-    OUTPUT_STRIP_TRAILING_WHITESPACE)
-if(VER_OUTPUT MATCHES "XP")
-    message(STATUS "Windows XP platform.")
-    add_definitions(-D_WIN32_WINNT=0x0501)
-else()
-    message(STATUS "Windows NT platform.")
-    add_definitions(-D_WIN32_WINNT=0x0601)
-endif()
-endif()
-
 if (DEFINED USE_TRANSM_TEST)
 message(STATUS "USE USE_TRANSM_TEST ${USE_TRANSM_TEST}")
 add_definitions(-DUSE_TRANSM_TEST)