diff --git a/build-aux/ltmain.in b/build-aux/ltmain.in
index 1b8d5031..af4970be 100644
--- a/build-aux/ltmain.in
+++ b/build-aux/ltmain.in
@@ -3638,7 +3638,7 @@ EOF
 #endif
 #include <stdio.h>
 #include <stdlib.h>
-#if defined (WIN32) && !defined (__GNUC_)
+#if defined (_WIN32) && !defined (__GNUC__)
 # include <direct.h>
 # include <process.h>
 # include <io.h>