diff --git a/expat/CMakeLists.txt b/expat/CMakeLists.txt
index d3bb7b80..3add30db 100755
--- a/expat/CMakeLists.txt
+++ b/expat/CMakeLists.txt
@@ -50,7 +50,6 @@ if(MSVC)
     add_definitions(-D_CRT_SECURE_NO_WARNINGS -wd4996)
 endif(MSVC)
 if(WIN32)
-    add_definitions(-DWIN32)
     set(CMAKE_DEBUG_POSTFIX "d" CACHE STRING "Add a suffix, usually d on Windows")
 endif(WIN32)