diff --git a/application/basilisk/base/content/browser.css b/application/basilisk/base/content/browser.css
index a2c2559d6..776cea110 100644
--- a/application/basilisk/base/content/browser.css
+++ b/application/basilisk/base/content/browser.css
@@ -205,7 +205,7 @@ toolbar[customizing] > .overflow-button {
   display: none;
 }
 
-%ifdef CAN_DRAW_IN_TITLEBAR
+%ifdef MOZ_CAN_DRAW_IN_TITLEBAR
 #main-window:not([chromemargin]) > #titlebar,
 #main-window[inFullscreen] > #titlebar,
 #main-window[inFullscreen] .titlebar-placeholder,
diff --git a/application/basilisk/base/content/browser.xul b/application/basilisk/base/content/browser.xul
index 06d20866d..81370a4e3 100644
--- a/application/basilisk/base/content/browser.xul
+++ b/application/basilisk/base/content/browser.xul
@@ -44,7 +44,7 @@
         titlemodifier_normal="&mainWindow.titlemodifier;"
         titlemodifier_privatebrowsing="&mainWindow.titlemodifier; &mainWindow.titlePrivateBrowsingSuffix;"
 #endif
-#ifdef CAN_DRAW_IN_TITLEBAR
+#ifdef MOZ_CAN_DRAW_IN_TITLEBAR
 #ifdef XP_WIN
         chromemargin="0,2,2,2"
 #else
@@ -390,7 +390,7 @@
              onpopupshowing="UpdateDynamicShortcutTooltipText(this);"/>
   </popupset>
 
-#ifdef CAN_DRAW_IN_TITLEBAR
+#ifdef MOZ_CAN_DRAW_IN_TITLEBAR
 <vbox id="titlebar">
   <hbox id="titlebar-content">
     <spacer id="titlebar-spacer" flex="1"/>
@@ -437,7 +437,7 @@
 #include browser-menubar.inc
       </toolbaritem>
 
-#ifdef CAN_DRAW_IN_TITLEBAR
+#ifdef MOZ_CAN_DRAW_IN_TITLEBAR
 #ifndef XP_MACOSX
       <hbox class="titlebar-placeholder" type="caption-buttons" ordinal="1000"
             id="titlebar-placeholder-on-menubar-for-caption-buttons" persist="width"
@@ -502,7 +502,7 @@
 #if !defined(MOZ_WIDGET_GTK)
       <hbox class="private-browsing-indicator" skipintoolbarset="true"/>
 #endif
-#ifdef CAN_DRAW_IN_TITLEBAR
+#ifdef MOZ_CAN_DRAW_IN_TITLEBAR
       <hbox class="titlebar-placeholder" type="caption-buttons"
             id="titlebar-placeholder-on-TabsToolbar-for-captions-buttons" persist="width"
 #ifndef XP_MACOSX
diff --git a/application/basilisk/base/jar.mn b/application/basilisk/base/jar.mn
index 583401915..6abdb79e8 100644
--- a/application/basilisk/base/jar.mn
+++ b/application/basilisk/base/jar.mn
@@ -75,7 +75,7 @@ browser.jar:
 #endif
         content/browser/browser-sidebar.js            (content/browser-sidebar.js)
 *       content/browser/browser-tabPreviews.xml       (content/browser-tabPreviews.xml)
-#ifdef CAN_DRAW_IN_TITLEBAR
+#ifdef MOZ_CAN_DRAW_IN_TITLEBAR
         content/browser/browser-tabsintitlebar.js       (content/browser-tabsintitlebar.js)
 #else
         content/browser/browser-tabsintitlebar.js       (content/browser-tabsintitlebar-stub.js)
diff --git a/application/basilisk/base/moz.build b/application/basilisk/base/moz.build
index b21c0ac29..2e5cde1d6 100644
--- a/application/basilisk/base/moz.build
+++ b/application/basilisk/base/moz.build
@@ -13,9 +13,6 @@ if CONFIG['MOZ_WIDGET_TOOLKIT'] in ('windows', 'gtk2', 'gtk3', 'cocoa'):
     DEFINES['HAVE_SHELL_SERVICE'] = 1
     DEFINES['CONTEXT_COPY_IMAGE_CONTENTS'] = 1
 
-if CONFIG['MOZ_WIDGET_TOOLKIT'] in ('windows', 'cocoa'):
-    DEFINES['CAN_DRAW_IN_TITLEBAR'] = 1
-
 if CONFIG['MOZ_WIDGET_TOOLKIT'] in ('windows', 'gtk2', 'gtk3'):
     DEFINES['MENUBAR_CAN_AUTOHIDE'] = 1
 
diff --git a/application/basilisk/components/customizableui/content/customizeMode.inc.xul b/application/basilisk/components/customizableui/content/customizeMode.inc.xul
index b665630a2..28ce568c7 100644
--- a/application/basilisk/components/customizableui/content/customizeMode.inc.xul
+++ b/application/basilisk/components/customizableui/content/customizeMode.inc.xul
@@ -19,7 +19,7 @@
     <vbox id="customization-palette" class="customization-palette"/>
     <spacer id="customization-spacer"/>
     <hbox id="customization-footer">
-#ifdef CAN_DRAW_IN_TITLEBAR
+#ifdef MOZ_CAN_DRAW_IN_TITLEBAR
       <button id="customization-titlebar-visibility-button" class="customizationmode-button"
               label="&customizeMode.titlebar;" type="checkbox"
 #NB: because oncommand fires after click, by the time we've fired, the checkbox binding
diff --git a/application/basilisk/components/customizableui/moz.build b/application/basilisk/components/customizableui/moz.build
index 5797a03b0..f5c34aa93 100644
--- a/application/basilisk/components/customizableui/moz.build
+++ b/application/basilisk/components/customizableui/moz.build
@@ -19,6 +19,3 @@ EXTRA_JS_MODULES += [
 EXTRA_PP_JS_MODULES += [
     'CustomizableUI.jsm',
 ]
-
-if CONFIG['MOZ_WIDGET_TOOLKIT'] in ('windows', 'cocoa'):
-    DEFINES['CAN_DRAW_IN_TITLEBAR'] = 1
diff --git a/application/basilisk/confvars.sh b/application/basilisk/confvars.sh
index 824067e3a..cb97e5127 100644
--- a/application/basilisk/confvars.sh
+++ b/application/basilisk/confvars.sh
@@ -48,6 +48,12 @@ MOZ_SAFE_BROWSING=
 MOZ_GAMEPAD=1
 MOZ_AV1=1
 MOZ_SECURITY_SQLSTORE=1
+
+if test "$OS_ARCH" = "WINNT" -o \
+        "$OS_ARCH" = "Darwin"; then
+  MOZ_CAN_DRAW_IN_TITLEBAR=1
+fi
+
 # Disable checking that add-ons are signed by the trusted root
 MOZ_ADDON_SIGNING=0
 MOZ_REQUIRE_SIGNING=0
diff --git a/application/basilisk/themes/osx/moz.build b/application/basilisk/themes/osx/moz.build
index b787ab08e..8b611040d 100644
--- a/application/basilisk/themes/osx/moz.build
+++ b/application/basilisk/themes/osx/moz.build
@@ -8,6 +8,4 @@ DIRS += ['communicator']
 
 JAR_MANIFESTS += ['jar.mn']
 
-DEFINES['CAN_DRAW_IN_TITLEBAR'] = 1
-
 include('../tab-svgs.mozbuild')
diff --git a/application/basilisk/themes/shared/customizableui/customizeMode.inc.css b/application/basilisk/themes/shared/customizableui/customizeMode.inc.css
index d99933388..8535637ee 100644
--- a/application/basilisk/themes/shared/customizableui/customizeMode.inc.css
+++ b/application/basilisk/themes/shared/customizableui/customizeMode.inc.css
@@ -182,7 +182,7 @@
   height: 24px;
 }
 
-%ifdef CAN_DRAW_IN_TITLEBAR
+%ifdef MOZ_CAN_DRAW_IN_TITLEBAR
 #customization-titlebar-visibility-button > .button-box > .button-text,
 %endif
 #customization-lwtheme-button > .box-inherit > .box-inherit > .button-text {
@@ -198,7 +198,7 @@
   background-size: contain;
 }
 
-%ifdef CAN_DRAW_IN_TITLEBAR
+%ifdef MOZ_CAN_DRAW_IN_TITLEBAR
 #customization-titlebar-visibility-button {
   list-style-image: url("chrome://browser/skin/customizableui/customize-titleBar-toggle.png");
   -moz-image-region: rect(0, 24px, 24px, 0);
@@ -222,7 +222,7 @@
     -moz-image-region: rect(0, 96px, 48px, 48px);
   }
 }
-%endif /* CAN_DRAW_IN_TITLEBAR */
+%endif /* MOZ_CAN_DRAW_IN_TITLEBAR */
 
 #main-window[customize-entered] #customization-panel-container {
   background-image: url("chrome://browser/skin/customizableui/customizeMode-separatorHorizontal.png"),
diff --git a/application/basilisk/themes/windows/moz.build b/application/basilisk/themes/windows/moz.build
index b787ab08e..8b611040d 100644
--- a/application/basilisk/themes/windows/moz.build
+++ b/application/basilisk/themes/windows/moz.build
@@ -8,6 +8,4 @@ DIRS += ['communicator']
 
 JAR_MANIFESTS += ['jar.mn']
 
-DEFINES['CAN_DRAW_IN_TITLEBAR'] = 1
-
 include('../tab-svgs.mozbuild')