Index: lib/xvfs/xvfs.tcl
==================================================================
--- lib/xvfs/xvfs.tcl
+++ lib/xvfs/xvfs.tcl
@@ -15,11 +15,11 @@
 		foreach error $errors {
 			puts $channel "error: $error"
 		}
 		puts $channel ""
 	}
-	puts $channel "Usage: dir2c \[--help\] \[--output <filename>\] --directory <rootDirectory> --name <fsName>"
+	puts $channel "Usage: dir2c \[--help\] \[--set-mode {flexible|standalone|client}\] \[--output <filename>\] --directory <rootDirectory> --name <fsName>"
 	flush $channel
 }
 
 proc ::xvfs::sanitizeCString {string} {
 	set output [join [lmap char [split $string ""] {
@@ -247,11 +247,11 @@
 				set rootDirectory $val
 			}
 			"--name" {
 				set fsName $val
 			}
-			"--output" - "--header" {
+			"--output" - "--header" - "--set-mode" {
 				# Ignored, handled as part of some other process
 			}
 			default {
 				printHelp stderr [list "Invalid option: $arg $val"]
 				exit 1
@@ -307,10 +307,18 @@
 proc ::xvfs::staticIncludeHeader {pathToHeaderFile} {
 	set fd [open $pathToHeaderFile]
 	::xvfs::staticIncludeHeaderData [read $fd]
 	close $fd
 }
+
+proc ::xvfs::setSpecificMode {mode} {
+	::minirivet::_emitOutput "#undef XVFS_MODE_SERVER\n"
+	::minirivet::_emitOutput "#undef XVFS_MODE_CLIENT\n"
+	::minirivet::_emitOutput "#undef XVFS_MODE_FLEXIBLE\n"
+	::minirivet::_emitOutput "#undef XVFS_MODE_STANDALONE\n"
+	::minirivet::_emitOutput "#define XVFS_MODE_[string toupper $mode] 1\n"
+}
 
 proc ::xvfs::_tryFit {list} {
 	set idx -1
 	set lastItem -100000
 	foreach item $list {

Index: xvfs-create
==================================================================
--- xvfs-create
+++ xvfs-create
@@ -16,10 +16,17 @@
 foreach {arg val} $argv {
 	switch -exact -- $arg {
 		"--output" {
 			set outputFile $val
 		}
+		"--set-mode" {
+			if {$mode ne "run"} {
+				error "--set-mode may not be used with --dump-tcl"
+			}
+
+			set emitSpecificMode $val
+		}
 		"--header" {
 			set headerFile $val
 		}
 	}
 }
@@ -50,14 +57,19 @@
 
 		if {[info exists outputFile]} {
 			set fd [open $outputFile w]
 			::xvfs::setOutputChannel $fd
 		}
+
+		if {[info exists emitSpecificMode]} {
+			::xvfs::setSpecificMode $emitSpecificMode
+		}
 
 		if {[info exists headerFile]} {
 			::xvfs::staticIncludeHeader $headerFile
 		}
+
 		::xvfs::run {*}$argv
 
 		if {[info exists fd]} {
 			close $fd
 		}
@@ -93,12 +105,19 @@
 			foreach {arg val} $argv {
 				switch -exact -- $arg {
 					"--output" {
 						set ::minirivet::_outputChannel [open $val w]
 					}
+					"--set-mode" {
+						set emitSpecificMode $val
+					}
 				}
 			}
+			if {[info exists emitSpecificMode]} {
+				::xvfs::setSpecificMode $emitSpecificMode
+			}
+
 		}
 		puts ""
 		puts [list ::minirivet::_emitOutput $core_header_data]
 		puts ""