--- a/browser/confvars.sh
+++ b/browser/confvars.sh
@@ -8,31 +8,16 @@ MOZ_APP_VENDOR=Mozilla
 MOZ_UPDATER=1
 MOZ_PHOENIX=1
 
 if test "$OS_ARCH" = "WINNT" -o \
         "$OS_ARCH" = "Linux"; then
   MOZ_BUNDLED_FONTS=1
 fi
 
-if test "$OS_ARCH" = "WINNT"; then
-  if ! test "$HAVE_64BIT_BUILD"; then
-    if test "$MOZ_UPDATE_CHANNEL" = "nightly" -o \
-            "$MOZ_UPDATE_CHANNEL" = "aurora" -o \
-            "$MOZ_UPDATE_CHANNEL" = "beta" -o \
-            "$MOZ_UPDATE_CHANNEL" = "beta-dev" -o \
-            "$MOZ_UPDATE_CHANNEL" = "release" -o \
-            "$MOZ_UPDATE_CHANNEL" = "release-dev"; then
-      if ! test "$MOZ_DEBUG"; then
-        MOZ_STUB_INSTALLER=1
-      fi
-    fi
-  fi
-fi
-
 # Enable building ./signmar and running libmar signature tests
 MOZ_ENABLE_SIGNMAR=1
 
 MOZ_APP_VERSION=$FIREFOX_VERSION
 MOZ_APP_VERSION_DISPLAY=$FIREFOX_VERSION_DISPLAY
 MOZ_EXTENSIONS_DEFAULT=" gio"
 # MOZ_APP_DISPLAYNAME will be set by branding/configure.sh
 # MOZ_BRANDING_DIRECTORY is the default branding directory used when none is

--- a/browser/moz.configure
+++ b/browser/moz.configure
@@ -14,9 +14,20 @@ imply_option('MOZ_SERVICES_CLOUDSYNC', T
 @depends(target)
 def maintenance_service(target):
     if target.os == 'WINNT':
         return True
 
 set_config('MOZ_MAINTENANCE_SERVICE', maintenance_service)
 set_define('MOZ_MAINTENANCE_SERVICE', maintenance_service)
 
+@depends(target, have_64_bit, '--enable-debug', update_channel)
+def stub_installer(target, have_64_bit, debug, update_channel):
+    if all([target.os == 'WINNT',
+            not have_64_bit,
+            not debug,
+            update_channel in ('nightly', 'aurora', 'beta',
+                               'beta-dev', 'release', 'release-dev')]):
+        return True
+
+set_config('MOZ_STUB_INSTALLER', stub_installer)
+
 include('../toolkit/moz.configure')

--- a/old-configure.in
+++ b/old-configure.in
@@ -5451,17 +5451,16 @@ AC_SUBST(MOZ_FEEDS)
 
 AC_SUBST(MOZ_UNIVERSALCHARDET)
 AC_SUBST(ACCESSIBILITY)
 AC_SUBST(MOZ_SPELLCHECK)
 AC_SUBST(MOZ_ANDROID_ANR_REPORTER)
 AC_SUBST(MOZ_CRASHREPORTER)
 AC_SUBST(MOZ_CRASHREPORTER_INJECTOR)
 AC_SUBST(MOZ_CRASHREPORTER_UPLOAD_FULL_SYMBOLS)
-AC_SUBST(MOZ_STUB_INSTALLER)
 AC_SUBST(MOZ_VERIFY_MAR_SIGNATURE)
 AC_SUBST(MOZ_ENABLE_SIGNMAR)
 AC_SUBST(MOZ_UPDATER)
 
 AC_SUBST(MOZ_ANGLE_RENDERER)
 AC_SUBST(MOZ_D3D_CPU_SUFFIX)
 AC_SUBST(MOZ_HAS_WINSDK_WITH_D3D)
 AC_SUBST(MOZ_D3DCOMPILER_VISTA_DLL)