diff --git a/src/libCom/Makefile b/src/libCom/Makefile
index f6a3bf71f..1b4be6e62 100644
--- a/src/libCom/Makefile
+++ b/src/libCom/Makefile
@@ -161,6 +161,7 @@ SRCS += osdFindSymbol.c
 SRCS += osdInterrupt.c
 SRCS += osdPoolStatus.c
 SRCS += osdEnv.c
+osdEnv_CFLAGS_WIN32= -U__STDC__
 
 SRCS += osdThread.c
 SRCS += osdMutex.c