diff --git a/CMakeLists.txt b/CMakeLists.txt
index 1de7a0e..3471701 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -172,7 +172,7 @@ function(set_target_common_gns_properties TGT)
 	elseif(CMAKE_SYSTEM_NAME MATCHES FreeBSD)
 		target_compile_definitions(${TGT} PUBLIC POSIX FREEBSD)
 	elseif(CMAKE_SYSTEM_NAME MATCHES Windows)
-		#target_compile_definitions(${TGT} PUBLIC WIN32)
+		target_compile_definitions(${TGT} PUBLIC _WINDOWS)
 		if(CMAKE_CXX_COMPILER_ID MATCHES "MSVC")
 			if(NOT Protobuf_USE_STATIC_LIBS)
 				target_compile_definitions(${TGT} PRIVATE PROTOBUF_USE_DLLS)