Index: build/web/kitcreator.vfs/index.rvt
==================================================================
--- build/web/kitcreator.vfs/index.rvt
+++ build/web/kitcreator.vfs/index.rvt
@@ -125,10 +125,13 @@
 					set build_options(staticlibssl) 1
 				}
 				"option_staticpkgs" {
 					set build_options(staticpkgs) 1
 				}
+				"option_tclutfmax6" {
+					set build_options(tclutfmax6) 1
+				}
 				"option_storage" {
 					switch -- $args($arg) {
 						"mk4" - "zip" - "cvfs" {
 							set build_options(storage) $args($arg)
 						}
@@ -365,10 +368,11 @@
             <input type="checkbox" name="option_debug">Kit: Debugging Build<br>
             <input type="checkbox" name="option_kitdll" id="option_kitdll">Kit: Build Library (KitDLL)<br>
             <input type="checkbox" name="option_dynamictk" id="option_dynamictk">Kit: Always link Tk dynamically (if Tk is built)<br>
             <input type="checkbox" name="option_minbuild">Kit: "Minimal" build (remove extra packages shipped as part of Tcl and reduce encodings)<br>
             <input type="checkbox" name="option_staticpkgs">Kit: Statically link packages in pkgs directory<br>
+            <input type="checkbox" name="option_tclutfmax6">Kit: TCL_UTF_MAX=6 (incompatibility with standard Tcl)<br>
             <input type="checkbox" name="option_staticlibssl">TLS: Statically link to LibSSL
           </td>
         </tr>
 	<tr>
 		<td>Kit Storage:</td>

Index: build/web/process_queue
==================================================================
--- build/web/process_queue
+++ build/web/process_queue
@@ -111,10 +111,15 @@
 			}
 			"staticpkgs" {
 				if {$value} {
 					set ::env(KC_TCL_STATICPKGS) 1
 				}
+			}
+			"tclutfmax6" {
+				if {$value} {
+					set ::env(KC_TCL_UTF_MAX) 6
+				}
 			}
 			"staticmk4" {
 			}
 		}
 	}
@@ -130,11 +135,11 @@
 	catch {
 		set cmd [list $script $buildinfo(tcl_version) {*}$args]
 		set fd [open "${outfile}.log" w+]
 		puts $fd "Running: export KITCREATOR_PKGS=\"$::env(KITCREATOR_PKGS)\""
 
-		foreach variable [list STRIP STATICTK KITCREATOR_MINENCODINGS KITCREATOR_MINBUILD KC_TLS_LINKSSLSTATIC KC_TCL_STATICPKGS] {
+		foreach variable [list STRIP STATICTK KITCREATOR_MINENCODINGS KITCREATOR_MINBUILD KC_TLS_LINKSSLSTATIC KC_TCL_STATICPKGS KC_TCL_UTF_MAX] {
 			if {[info exists ::env($variable)]} {
 				puts $fd "Running: export $variable=\"$::env($variable)\""
 			}
 		}
 

ADDED   tcl/patchscripts/tcl-utf-max.sh
Index: tcl/patchscripts/tcl-utf-max.sh
==================================================================
--- /dev/null
+++ tcl/patchscripts/tcl-utf-max.sh
@@ -0,0 +1,11 @@
+#! /bin/bash
+
+if [ -z "${KC_TCL_UTF_MAX}" ]; then
+	exit 0
+fi
+
+sed 's@^# *define TCL_UTF_MAX .*$@#define TCL_UTF_MAX '"${KC_TCL_UTF_MAX}"'@' generic/tcl.h > generic/tcl.h.new
+cat generic/tcl.h.new > generic/tcl.h
+rm -f generic/tcl.h.new
+
+exit 0