configure: Don't define _WIN64 on the command line to avoid trouble with system headers.
diff --git a/configure.ac b/configure.ac
index b9a5b24..5d43d53 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1431,8 +1431,7 @@
case $host_cpu in
*i[[3456789]]86*) WINE_CHECK_DEFINE([__i386__]) ;;
- *x86_64*) WINE_CHECK_DEFINE([__x86_64__])
- WINE_CHECK_DEFINE([_WIN64]) ;;
+ *x86_64*) WINE_CHECK_DEFINE([__x86_64__]) ;;
*alpha*) WINE_CHECK_DEFINE([__ALPHA__]) ;;
*sparc*) WINE_CHECK_DEFINE([__sparc__]) ;;
*powerpc*) WINE_CHECK_DEFINE([__powerpc__]) ;;