Index: xvfs.c.rvt
==================================================================
--- xvfs.c.rvt
+++ xvfs.c.rvt
@@ -42,10 +42,13 @@
 
 	set ::xvfs::hashNameThreshold 3
 	if {[info exists ::env(XVFS_CREATE_HASH_NAME_THRESHOLD)]} {
 		set ::xvfs::hashNameThreshold $::env(XVFS_CREATE_HASH_NAME_THRESHOLD)
 	}
+	if {$::xvfs::hashNameThreshold < 0} {
+		set ::xvfs::hashNameThreshold [expr {2**31}]
+	}
 	xvfs::main $argv
 
 	proc emitFilenameVerification {indentLevel outputFileNameLen outputFileIndexes} {
 		set indent [string repeat "\t" $indentLevel]
 		foreach outputFileIndex $outputFileIndexes {