Exclude building Mono 4.0 assemblies.
diff --git a/nant.build b/nant.build
index 6b58bef..615e8ec 100644
--- a/nant.build
+++ b/nant.build
@@ -43,6 +43,7 @@
 	<property name="build.netcf-2.0.skip" value="true" />
 	<property name="build.netcf-3.5.skip" value="true" />
 	<property name="build.mono-2.0.skip" value="true" />
+	<property name="build.mono-4.0.skip" value="true" />
 
 	<target name="vendor-init" description="Initializes Vendor library from local repository.">
 		<!--